Fiberglass Pools Archives - Page 2 of 4

Examining the Elements Involved in Factoring LSI

Posted on April 10, 2024June 10, 2026 by kristin

Maintaining balanced pool water chemistry in your fiberglass pool is truly a balancing act. Each of the six factors that calculate the Langelier Saturation Index (LSI) can ebb and flow, although some are more reactionary and volatile than others. While maintaining all six factors may feel like a juggling act, understanding what they are, how they interact, and their impact on your pool is critical to keeping the LSI balanced and your water in equilibrium.

The Critical Role of pH

pH, or “potential of hydrogen,” is the most critical variable in water chemistry balance. While alterations of any involved equation variables can affect your water balance, a change in pH can have ten times the effect compared to other LSI factors.

pH levels indicate water’s acidity or basicity. They range from 0 to 14, with 0 being very acidic, 7 being neutral, and 14 being very basic. Chlorine and other sanitizers will only remain effective and function correctly within specific pH ranges—namely, the range between 7.2 and 7.4 deemed ideal for swimming pools. Hydrochloric or muriatic acid can lower high pH levels, while a low-pH pool will need an alkaline boost from sodium carbonate.

The best thing an owner can do for the health and safety of their pool and its frequent swimmers is to regularly test the pH and other chemical levels. Daily testing and checks before and after each use are recommended and will help you become more familiar with how various factors, including some outside your control, affect your pH and overall LSI levels.

Total Alkalinity

Alkalinity is often called “the yin to pH’s yang,” as the two are related. Alkalinity measures water’s capacity to withstand changes in pH. In fiberglass pools, recommended total alkalinity levels range from 80 to 120 parts per million.

Low alkalinity makes water corrosive, causing stains and etching on your pool’s surface. Water will become depository if alkalinity rises above the recommended range for fiberglass pools (120 ppm). As a result, pool surface scaling occurs and a white cloudy film may appear, clogging filters and reducing circulation.

Total Dissolved Solids (TDS)

As the name implies, total dissolved solids (TDS) include chemicals or anything other than calcium that remains after water evaporates. These solids can include salts, metals, minerals, and other organic materials that have entered and dissolved within the pool water. We recommend that the TDS level be no higher than 1,500 ppm (or 1,000 ppm above safe salt level in saltwater pools). A high TDS level can lead to algae blooms, scaling, or other pool stains.

Cyanuric Acid (Chlorine Stabilizer)

Cyanuric acid (CYA) will prevent the sun’s ultraviolet rays from decomposing free chlorine in your pool water. Levels between 30 and 50 ppm are recommended, but higher levels don’t necessarily mean better results. If the cyanuric acid level reaches 100 ppm or above, chlorine’s effectiveness at killing bacteria and algae is compromised.

Calcium Hardness

A lower calcium hardness level in your pool water results in a softer and silkier it will feel on swimmers’ skin. Calcium hardness is also essential for maintaining water cleanliness and equipment operation. Regulated calcium hardness of less than 120 ppm will help keep pool materials looking and working their best. When calcium hardness is too low, the water becomes aggressive and corrosive. When too high, pH levels raise, leading to cloudy water, surface discoloration, and filter-clogging calcium deposits.

Temperature

The temperature factor is the only non-chemical component of water chemistry balance and your pool’s LSI. Utilizing a pool heater will make your temperature factor much easier to control. Many swimmers enjoy a “bathwater” feel and temperature, but water warmer than 82 degrees Fahrenheit can encourage bacteria or algae growth. Calcium deposits form more quickly in warmer water, while a too-cool pool makes it easier for water to begin corroding equipment.

Parents of infants and young children should consider keeping temperatures slightly higher into the upper 80s. However, a pool used primarily for exercise or competitive swim training should skew lower, between 77 and 82 degrees Fahrenheit. A good general rule for many pool owners is aiming for a water temperature between 77 degrees and the mid-80s. Keeping a constant temperature will help prevent bacteria and algae growth and improve the efforts of chlorine, saltwater, or other pool sanitation measures.

Every Factor is Important

Many pool owners and even pool service professionals habitually test for pH and chlorine, and occasionally they check the alkalinity. However, this approach ignores many critical LSI factors. Although they do not tend to change as rapidly, You should also regularly test calcium hardness, CYA, and TDS. By testing all six factors in your pool water, you will have a more clear and complete understanding of its LSI and water balance.

How Do I Balance My Pool Water Using LSI?

Posted on April 10, 2024June 10, 2026 by kristin

Balancing your pool water is essential for maintaining its clarity, safety, and longevity, especially for fiberglass pool owners. While pool water chemistry balance may seem complex, modern tools like the Orenda Technologies LSI Calculator have simplified the testing and adjustment process. This blog post will guide you through using Orenda’s app to achieve optimal water balance in your pool, ensuring it stays in beautiful condition without needing a degree in chemistry. We’ve included step-by-step instructions, complemented by screen-capture images, to make the process as straightforward as possible.

Editor’s Note: There are available alternatives to the Orenda app. Thursday Pools and Orenda have no relationship other than sharing a desire to help fiberglass pool owners properly maintain their water chemistry. If you want to get even more informed on water balance and related topics, check out Orenda’s library of educational videos, tutorials, and other resources.

Step 1: Download the Orenda App

The journey to balanced pool water begins with a simple download of the Orenda app, available on both iOS and Android platforms. This app significantly simplifies pool chemistry, particularly focusing on the Langelier Saturation Index (LSI), making it an indispensable tool for pool owners.

Step 2: Input Your Pool Details

Once you have downloaded and opened the app, the first step is to input your pool’s specific details, such as the volume of your pool in gallons and the water temperature, which are critical for accurate calculations. The app’s user-friendly interface guides you through entering these initial details.

Step 3: Enter Current Water Chemistry Levels

The next step involves inputting the current levels of various water chemistry variables that influence your pool’s LSI.

These include:

Water temperature
pH level
Calcium Hardness
Total Alkalinity
Cyanuric Acid stabilizer
Total Dissolved Solids

You’ll find a section on the left-hand side of the app dedicated to entering these values. Precise measurements at this stage are crucial for accurately assessing your pool’s water balance.

Also, note that the app includes levels for Chlorine and Phosphates. While these values don’t affect the LSI, they are essential in maintaining a healthy and safe pool.

Step 4: Adjusting for Optimal LSI

After entering your pool’s details and current chemistry levels, the real magic begins. The app allows you to tweak and adjust the values on the right-hand side of the screen to see how changes can affect your pool’s LSI.

The goal is to adjust these levels until you achieve a desired LSI value within the optimal range of -0.3 to +0.3. Note that for saltwater pools, we recommend a slightly tighter range of -0.2 to +0.2 to account for the unique chemistry of saltwater systems.

The app’s LSI indicator is highlighted in different colors depending on the status.

Over +0.30 is coded PURPLE, meaning your water can cause scaling on your equipment and gelcoat surface.
-0.30 to +0.30 is coded GREEN to indicate the ideal LSI balance.
-0.30 to -0.01 is YELLOW, meaning you’re close to balance but not quite there.
< -0.30 is coded RED to alert you to corrosive water that can damage your pool equipment and gelcoat surface.

The ideal target is as close to zero as possible. This interactive feature allows you to experiment with different adjustments to understand how each factor may affect your pool’s overall balance.

Step 5: Calculate and Correct

After adjusting your inputs to reach the ideal LSI range, hitting the “Calculate” button creates a customized list of actions and products needed to balance your pool water. It tells you what needs to be adjusted and recommends specific chemicals and quantities to achieve the desired balance. This step eliminates guesswork, ensuring you use the right products in the right amounts.

Step 6: Implement Recommendations

With a tailored action plan, the final step is implementing the app’s recommendations. Whether adjusting the pH, adding calcium hardness increaser, or balancing total alkalinity, follow the guidelines to bring your pool water into harmony.

Why Use the Orenda App?

Simplifies Complex Calculations

The Orenda app demystifies the complexity of water chemistry, breaking it down into simple and manageable steps. This guidance ensures that pool owners can maintain their pool’s health without needing deep technical knowledge.

Saves Time and Money

By providing precise recommendations, the app helps pool owners avoid over- or under-treating their pool, saving money on chemicals and preventing potential damage to the pool’s surface or equipment.

Enhances Pool Enjoyment

Regularly using the Orenda app to balance your pool water means clearer, safer water and a more enjoyable swimming experience for you and your family. It also extends the lifespan of your pool by preventing damage and other issues related to imbalanced water.

Balancing your pool water using the LSI doesn’t have to be daunting. With the Orenda Technologies LSI Calculator, achieving and maintaining optimal water balance is easier and more intuitive than ever. By following the simple steps outlined above and taking advantage of the app’s smart recommendations, you can ensure your pool remains an enjoyable oasis for years to come.

What is LSI?

Posted on April 9, 2024June 10, 2026 by kristin

LSI and Fiberglass Pool Chemistry

The Langelier Saturation Index (LSI) is a formula that the gunite pool industry adopted to determine water balance and predict whether water will form calcium scale or dissolve it. Some pool industry professionals insist you should focus strictly on LSI balance, but for fiberglass, that advice can damage your pool. However, an LSI calculator can be helpful for fiberglass pool owners as a secondary tool in keeping critical factors of water chemistry within fiberglass-safe target ranges.

What Are Fiberglass-Safe Water Chemistry Target Ranges?

pH: 7.2 to 7.4
Total Alkalinity (TA): 80 to 120 ppm
Free Chlorine (FC): 1 to 3 ppm
Cyanuric Acid (CYA): 30 to 50 ppm
Calcium Hardness (CH): Less than 120 ppm (NEVERt add calcium)
Total Dissolved Solids (TDS): Less than 1,500 ppm (or up to 1,000 ppm above your salt level)

Always use a stain and scale control or chelating and sequestering agent as part of routine care and for winterization. Never use calcium hypochlorite or any calcium-adding products in fiberglass pools. When pH, calcium, and chlorine are all elevated at the same time, the risk of damage to the fiberglass pool gelcoat increases significantly. If only one or two are high, the risk of damage is lower but still present.

What is LSI?

The Langelier Saturation Index was developed in the 1930s by Dr. Wilfred Langelier to help cities predict whether water would deposit calcium carbonate scale inside pipes or dissolve it. The concept later made its way into the pool industry because it’s an easy way to check water chemistry with respect to calcium carbonate.

Simply put, LSI looks at pH, alkalinity, temperature, and calcium levels together and estimates whether water is likely to scale (represented with a positive-number LSI) or dissolve calcium (negative LSI).

Why is LSI Secondary for Fiberglass Pools?

Concrete and plaster pools contain calcium in their walls. If the water is too “hungry” (what pool pros call “aggressive water”), it pulls calcium out of those surfaces, causing rough spots or etching.

Fiberglass pools are different. The shell doesn’t contain calcium, so aggressive water won’t leach anything from it. Instead, the bigger risk is the opposite: too much calcium in the water. When high calcium combines with high pH or high chlorine, it can cause discoloration on the gelcoat. That’s why adding calcium to “fix” LSI—something that works for concrete—can actually damage fiberglass.

How Do I Use LSI in a Fiberglass-Safe Way? Practical Steps to Take

Think of LSI as a final check after you’ve set your fiberglass targets.

Dial in the targets first: pH between 7.2 and 7.4, TA between 80 and 120 ppm, FC at 1 to 3 ppm, CYA at 30 to 50 ppm, and CH less than 120 ppm.
Check LSI last: Aim for roughly -0.30 to +0.30.

- In cold water, from late fall through winter, a slightly negative LSI is acceptable.
- Do not push water chemistry factors outside of fiberglass-safe ranges in order to hit perfectly balanced 0.0.

If LSI is too positive and water is scale-prone:

- Bring pH toward 7.2 to 7.4 without overshooting high.
- Confirm TA is within 80 to 120 ppm.
- Do not add calcium. Keep using your stain and scale control.

If LSI is too negative and water is aggressive:

- Make sure pH is not below 7.2 and adjust gently.
- Bring TA within 80 to 120 ppm.
- A cold-weather LSI total slightly below -0.30 can be acceptable for fiberglass.

Looking for more information on water chemistry and fiberglass pool maintenance? Explore Thursday Pools’ Ultimate Fiberglass Pool Maintenance Guide.

And if you’re ready for personalized advice or want to talk about water chemistry ranges with a local pool pro, connect with an independent Thursday Pools dealer near you.

Frequently Asked Questions About LSI

My LSI is +0.5 but my pH is 7.6. Should I add calcium to bring it down?

No. For fiberglass, keep calcium hardness levels less than 120 ppm. Lower pH toward 7.2 to 7.4 and verify total alkalinity between 80 and 120. Keep using a stain and scale control product. Calcium may fix LSI for concrete pools, but it causes more harm than good in fiberglass.

What if my fill water is hard?

Use a stain and scale control product and manage pH and total alkalinity. The goal is to prevent calcium fallout onto the gelcoat, not raise calcium.

Can I “balance for LSI” during winter?

You can allow a slightly negative LSI in cold water, but always stay within fiberglass-safe pH and total alkalinity ranges, keep calcium hardness less than 120 ppm, and use additional stain and scale control at pool closing.

Do I need to calculate LSI every time I test my pool water?

No. Focus first on fiberglass-safe water chemistry ranges for pH, alkalinity, chlorine, and calcium.

Why is calcium hardness so important for fiberglass pools?

Fiberglass shells don’t need calcium for structural protection, unlike concrete pools. Too much calcium in fiberglass pools leads to scale, discoloration, and rough surfaces, so always keep levels less than 120 ppm. If you have hard source water and your calcium is high, be sure to use a stain and scale control product.

Is a Fiberglass Pool Shell Right For Your Pool?

Posted on April 1, 2024June 10, 2026 by krista

If you are looking into buying and researching inground pools, you have likely discovered that pool forms are made of concrete, vinyl-liner, or a fiberglass pool shell. In this post, we’ll take a closer look at fiberglass pool shells so you can determine if one may be right for you.

What is a fiberglass pool made of?

Fiberglass has become a well-known material in the past 50 years. It’s used to make boats, automobile parts and, of course, pools! Fiberglass material is quite literally fibers of glass. In the manufacturing process, fiberglass is flexible and thin, almost hair-like. Unlike hard, solid shards of glass, fiberglass doesn’t shatter or cut you because the fibers are heated until they’re molten and become a sticky, gooey texture. It is then forced through superfine holes that create glass filaments that are so thin that they are measured in microns.

These thin threads of fiberglass are woven into larger swatches of material. For strength and durability, a fiberglass pool shell is made of more than fiberglass. What makes the material even stronger than metals by weight is the thermoplastic polymer resins that are added.

Through years of testing and our commitment to continuous improvement, Thursday Pools has developed durably-crafted composite pools. We’ve gotten our fiberglass pool shell recipe just right by manufacturing it in multiple layers of the best available ingredients.
We take quality and durability seriously. To assess precisely how many layers of strength are needed throughout high-stress points and each area of the pool, our engineers conducted finite element analysis (FEA). The results affect how many layers of the following ingredients will be required throughout the pool shell.

Gel Coat
Our pool surface gel coat is designed to last and look luxurious. It’s smooth, resistant to algae, and a dog’s claws won’t cause a scratch. Thursday Pools uses a high-quality gel coat so you can feel confident in your purchase, knowing that your pool surface is one of the most tested and reputable on the market.
Vinyl Ester Resin Barrier Coat
Our vinyl ester resin barrier coat helps enhance the longevity and performance of the fiberglass structure by providing an additional layer of protection against moisture and chemical degradation. Our vinyl ester barrier coat prevents potential blistering and protects the surface finish of your pool.
Chopped and Hand-Laid Fiberglass
For several pool layers, fiberglass is combined with 100 percent isophthalic polyester resin and no fillers. This type of resin is used where strength and durability are a must. Despite the costs and time involved, Thursday Pools uses both equipment-applied chopped fiberglass and hand-laid applied fiberglass to achieve the optimal physical properties that a best-in-class fiberglass pool requires.
Custom Stitch Mats
Our hand-laid stitch mats provide additional strength, stability, and reinforcement. The stitching helps hold the fibers in place, preventing them from shifting or becoming misaligned, enhancing the pool shell’s structural integrity and impact resistance.

Honeycomb Core
Thursday Pools uses a honeycomb core structure to add vertical and horizontal supports throughout the pool. This construction technique applies to all horizontal surfaces above the floor, such as steps, benches, and tanning ledges. It is also reinforced in vertical strips along the pool wall.

Should I buy a fiberglass inground pool?

Fiberglass pool shells are beautiful, durable, and even somewhat flexible, making them more able to withstand weather conditions and ground movement. The malleability of fiberglass also allows us to create unique features such as sun shelves, tanning ledges, benches, swim-outs, steps, and even a zero entry. Here are some other questions to ask:

What shapes and sizes do fiberglass pool shells come in? We manufacture a variety of fiberglass pool shapes to fulfill your backyard dreams. We craft our pools to fit how our customers use them the most—rectangle, freeform, big, and small. We have a pool for every personality and yard type! Our smallest pool (the sea turtle) is 9.5′ x 19.5′ and 4’6″ deep while our biggest pool (the Goliath) is 16′ x 41′ and 6’8″ deep. Plus, we build just about every size in between.
How long do fiberglass pools last? Can a fiberglass pool last 50 years? Yes! Fiberglass pools will last well over 50 years if you get it through a reputable manufacturer that uses high-quality materials and if the installation is done properly. We inspect each pool shell thoroughly before shipping it out and only distribute our pools through our dealer network to ensure proper installation.
If anything were to go wrong (and we hope it doesn’t), we’ve got you covered! Our 15-year surface warranty will warrant the surface of the pool from osmotic blistering. And our one-time transferable 35-year structural warranty protects against any leak due to structural failures caused by workmanship and material used in the manufacturing for the lifetime of the pool.
Are fiberglass pools affordable? When shopping for a fiberglass pool, how much do fiberglass pools cost? is probably one of the first questions you’ll ask. The cost of a fiberglass pool will vary depending on your particular project, pool size, and even where you’re located. That said, the average cost of an inground pool is $45,000 – $65,000.

Every inground pool install is unique. There may be hidden cost factors that you will need to consider, such as site preparation, access, permits, fencing, restoration, electrical, and dirt hauling. Click to get an estimate, or try using our pool cost calculator. It will give you a ballpark figure based on the size of the pool and other items that are unique to your project. For more information, contact a dealer in your area!

Choosing Between Gunite and Fiberglass? A Guide.

Posted on April 1, 2024July 29, 2026 by krista

A GUIDE TO CHOOSING BETWEEN GUNITE AND FIBERGLASS.

Inground pools come in three different types—vinyl, gunite, and fiberglass—so determining what’s a right fit for you requires a little research. If you’ve arrived at the point where it’s a decisionon fiberglass vs gunite (concrete), you’ve narrowed your decision tree a bit by throwing out vinyl as an option. This post will consider a concrete pool vs fiberglass pool to help you narrow your choices even further.

Buyer’s Checklist

The answers to the following questions can be differentiating factors of choosing a concrete vs fiberglass pool.

How will your pool be used? Is it a party backdrop, a sunning platform, or the wet arena of countless epic splash-sport battles?
Who will maintain the pool? If it’s you, what is the amount of time you’re willing to commit? If it’s someone else, what is the annual budget?
How big a pool do you want or need? Do you want a particular size, shape, or feature?
How much decking and landscaping?
Who will use the pool? Will it include children and pets?
Does your dealer provide a warranty and track record of installing durable pools?

About Concrete Pools

The first gunite pool was built in 1940. However, soon after, World War II stifled the industry. In post-war society, more homeowners started to purchase gunite pools. And today, depending on climate, gunite pools are still popular. For example, gunite pools can be more affordable in Florida and California, where the year-round temperature isn’t as extreme.

What are the Advantages of Concrete Pools

Gunite pool advantages lie in their customizability. For the pool buyer who wants to take an active hand in their pool design, gunite is often, but not always, the best option. Gunite pools are:

Highly customizable. Concrete pools are built in various shapes, sizes, and depths. If you’re looking for a unique pool design (e.g., the shape of a guitar or a palm tree), a concrete pool is for you.
Durable. Gunite pools are concrete! Like roads, sidewalks, and buildings, the walls and floor of a gunite pool are durable. While excessive surface cracks can cause staining, algae buildup, and calcium nodules resulting in the need to replaster, the surface is much stronger than vinyl liner pools.

What are the Disadvantages of Concrete Pools?

Aside from having a potentially higher upfront cost, the main disadvantages are the cost and time involved with maintaining the gunite and its plaster surface. The cost of ownership can catch some owners off-guard. Disadvantages of concrete pools are:

Higher lifetime costs. As you’re doing your pool research, you’ll likely ask, “Are fiberglass or gunite pools more expensive?” Aside from various cost factors, including price differences in temperate climates, there’s not a big upfront price difference between the gunite and fiberglass pool cost. They both have mid-range costs from $45,000-$65,000. However, once you’ve bought the pool, you’ll have to maintain it. That’s when concrete pool cost becomes an issue for many buyers; the estimated 10-year maintenance cost of a gunite pool is about $20,000 or more compared to a fiberglass pool that has an estimated 10-year maintenance cost of around $5,750.
Higher maintenance. When comparing fiberglass to gunite, one of the most important things to consider is how hard it can be to maintain the pool. People decide not to get a pool because they worry about maintenance and upkeep. If this is one of your concerns, consider that gunite pools require more maintenance than any other type of pool. If you own a concrete pool, you may spend around four to five hours per week on concrete pool maintenance compared to around one hour with fiberglass.
Cracking. Have you ever noticed cracks on outdoor patios made of concrete? A pool is no different. As the earth moves, the concrete is not flexible, and instead of moving with the earth, the concrete cracks. This brittleness leaves you with expensive repairs and an undesirable finish to your pool. A fiberglass pool shell offers flexibility, helping to prevent damage when the earth shifts.
Salt incompatible. Gunite is not the best move if you want a salt system in your pool. Salt gradually eats away at the cement finish as salt eats away a concrete driveway. If salt sits on the pool surface without dissolving, it can stain it in minutes. This salt damage also shortens the lifespan of the pool.
Rough-surfaces. You most likely wouldn’t play volleyball barefoot on concrete. In the pool, it’s not much different! The rough surfaces can snag your swimsuit and be hard on your feet. Gunite can also hurt your pets’ joints and paws.

About Fiberglass Pools

Fiberglass pools came into the swimming pool market in the 1950s and have tripled in popularity in the last 20 years. These pools have become a hot commodity due to innovative manufacturing techniques, easier installation, lower maintenance, and luxurious designs with unique features like zero-entry and tanning ledges! You can even choose fiberglass pool designs with a hot tub.

Advantages of Fiberglass Swimming Pools

Fiberglass pools have exploded with innovative shapes, features, and designs. The experience of installing and owning a fiberglass pool is one of pure pool enjoyment. It’s a bit of work, but the emphasis is on the fun. Fiberglass swimming pools are:

Durable. (We’ll speak to our designs since we know them best). Our fiberglass pool shell is like a giant sandwich, the composite sandwich of awesomeness, made of 9 layers of different materials, including gel coat, fiberglass (chopped and woven), honeycomb core, and 100% vinyl ester barrier coat. Fiberglass specialists manufacture the shell in multiple layers, with each layer serving to maximize the strength and durability of the entire structure. The layers help the fiberglass withstand weather conditions while retaining flexibility and resisting cracking.
Quick to install. Fiberglass pools go in easy and fast. Gunite pools can depend heavily on weather conditions and will roughly take three to six months to install, while fiberglass pools typically only take three to six weeks during non-busy seasons because they are pre-built on the mold and ready to go into the ground upon delivery!
Usually paired with a lifetime manufacturer warranty. Concrete builders typically don’t have a manufacturer; therefore, they don’t have a manufacturer warranty. If any warranty comes with a concrete pool, it’s typically only a workmanship warranty by the builder. Most (but not necessarily all) fiberglass pool manufacturers ensure every pool purchased and installed is warranted not to leak due to structural failures caused by workmanship and material used in the manufacturing for the pool’s lifetime. If choosing a fiberglass pool, check with your independent dealer for the pool manufacturer warranty.
The easiest pool to own. As mentioned before, the average time you will spend maintaining a fiberglass pool is only an hour or less per week. A fiberglass pool’s smooth, non-skid gel coat finish is 100 percent non-porous and non-reactive, so it doesn’t absorb chemicals or affect how they perform. Because the smooth gel coat makes fiberglass pools algae-resistant, you will use fewer chemicals in a fiberglass pool than you would a gunite pool. Fiberglass pools are also lower maintenance than other pool types, needing little more than essential vacuuming, skimming, and water testing. Less time and fewer chemicals mean fiberglass pool cost is lower on an annual basis.
Smooth on the surface. The smooth gel-coat surface on our fiberglass pools won’t snag your swimsuit or cause scratches! Because the pool surface is smooth, a frequently asked question is, “are fiberglass pools slippery?” No, you won’t have to worry about the surface being too slick on steps or tanning ledges in our fiberglass pools, thanks to our proprietary process of producing a non-slip gel-coat for certain surfaces on each pool. The tanning areas, seats, steps, and safety ledges have this proprietary surface finish that provides a non-slip surface while still being easy on the skin and smooth to the touch.

Disadvantages of Fiberglass Swimming Pools

Fiberglass pools aren’t for everyone. Small fiberglass pools and medium-sized fiberglass pools come in various shapes and designs, but there are limits. The disadvantages of fiberglass pools are:

They are limited in size options. A fiberglass pool is limited to the lengths, widths, and shapes installers can safely transport on the highway. Fiberglass pools generally can be a maximum of 16-feet wide and 40-feet long.
They are less customizable. Fiberglass pool manufacturing requires pre-made molds, so pool designs are limited to what molds the manufacturer already has or is developing. Luckily, as fiberglass has become more popular, manufacturers have plenty of pool design options to choose from that will fit most yards and suit many lifestyles.
They are not DIY. Fiberglass pools are not DIY-friendly. Fiberglass pools are hard to install for even the handiest of handymen. Fiberglass pool dealers have access to training, and they will have the equipment needed to complete the job without damaging the pool. Many people ask us, “Do fiberglass pools pop out of the ground?” Well, they actually can if they aren’t properly installed. Many fiberglass manufacturers do not sell directly to homeowners and sell only to an independent dealer network. The dealer installs your pool to the standards of the warranty.

If you are looking for a low-maintenance, fast-to-install, durable inground pool, fiberglass is a great way to go! If you’re interested in getting a fiberglass pool, the next step is to contact a dealer in your area and browse our pool designs to determine which is the best fit for your backyard oasis! If you want a quick ballpark estimate on the pool of your dreams, check out our pool cost calculator.

Large and Deep Fiberglass Pool Options

Posted on March 28, 2024August 7, 2026 by Karen

Pool owners love fiberglass pools for many reasons. Fiberglass pools are low-maintenance, quick to install and require fewer chemicals. Because fiberglass pools don’t have liners to replace or concrete that will eventually need to be replastered, they have the lowest lifetime cost of ownership over vinyl and gunite pools. They also have a smooth, durable finish that’s totally pet friendly, making them a sure bet for everyone in the family to love.

So why would anyone choose anything other than fiberglass? Well, there really aren’t too many reasons! However, for pool buyers looking for a large inground pool, the options in fiberglass are somewhat limited. Whereas gunite and vinyl pools are built on-site, fiberglass pools are made in a factory, out of a mold, and then transported in one piece to the home of their lucky new pool owners. There’s a limit to the size of what can be safely loaded, unloaded and transported, and on-site physical barriers like fences and trees also have to be taken into consideration for delivery.

Alas, there are some large fiberglass pool options that allow swimming pool owners the best of both worlds–big and low-maintenance. For your convenience, we have created comparison charts of large pools by various manufacturers in both rectangular and freeform shapes. While there are many similarities, certain aspects may be more appealing to you.

While large and deep fiberglass pools offer more than ample swim area for families, not everyone needs that much depth. If you want a pool that’s still generously sized but maybe not quite so deep, check out Thursday Pools models like Goliath, Aspen, or the Cathedral LX. With so many amazing options to choose from, you’re sure to find the perfect pool for you!

Do You Need to Brush a Fiberglass Pool?

Posted on November 8, 2022June 11, 2026 by kristin

Fiberglass pools are incredibly popular for good reasons. They are luxurious, long-lasting, and can create a beautiful backyard backdrop for many memorable moments with your family and friends. Like many major purchases and luxury items worth having, however, they require care and ongoing maintenance to stay in peak condition. Do you need to brush a fiberglass pool? That’s one of the most common questions homeowners ask when considering the prospective upkeep responsibilities with their pool purchase.

All pools, including fiberglass pools, have several essential maintenance tasks homeowners must perform—or hire local pool service professionals to handle—on a regular basis in order to keep them clean, safe, and functioning properly. The good news is that, thanks to their durable materials and innovative manufacturing methods, fiberglass pools require fewer chemicals and are easier to take care of than other inground pool types. Similar to other pool types, brushing is necessary with fiberglass pools, but it’s far from labor-intensive work and nothing to be afraid of.

Why Do You Brush a Fiberglass Pool?

While fiberglass pools are algae-resistant, dirt and debris buildup may become a daily occurrence with backyard landscaping surrounding the pool. Brushing your fiberglass pool helps prevent unwanted debris from settling in one place for too long and causing staining. After adding chemicals to your pool, brushing is a good agitating activity to help chemicals dissolve and circulate quickly.

How Often Should You Brush a Fiberglass Pool?

The frequency with which you should brush your fiberglass pool depends on how much dirt and debris get in your pool, how often you use the pool, and whether or not you have a pool cover. While your fiberglass pool may need more frequent brushing after prolonged periods of heavy use or bad weather, a good general rule of thumb is to give it a good brushing once or twice per week.

What Kind of Brush Do You Use for a Fiberglass Pool?

As opposed to the hard scrubbing necessary for pools with porous surfaces, fiberglass pools dictate a delicate, gentle touch to avoid scratching the gelcoat. The only type of brush you should use on a fiberglass pool is one with poly or nylon bristles. You should also consider your pool’s shape when choosing a brush for a fiberglass pool. If your pool is rectangular, choose a flat, rectangular brush to get into the corners. If your pool is freeform, choose a brush with a curved head.

How Do You Brush a Fiberglass Pool?

Push your soft-bristle brush over the entire pool surface, including the walls, floor, and any stairs, benches, or tanning ledges. Brushing the pool surfaces helps kick up caked-on dirt and debris in order to circulate it into the pool skimmer and filter system. Depending on the amount of dirt and debris, you may want to backwash your filter.

Do You Brush a Fiberglass Pool Before Vacuuming?

Brushing and vacuuming are both essential fiberglass pool maintenance responsibilities, but do not brush your pool directly before vacuuming. Brushing the pool “kicks up” the dirt and debris that was stuck to the surface, causing it to float in the water. Wait to run your pool vacuum until after particles reach the main drain and filter or settle back on the surface.

Keep Your Pool Smooth and Stunning

You will need to brush your fiberglass pool as part of your regular care and maintenance routine. Brushing is one of the most important ways you can keep your fiberglass pool’s surface beautiful, and it isn’t a very time-consuming or labor-intensive activity.

Looking for more information on fiberglass pool care? Explore Thursday Pools’ Ultimate Fiberglass Pool Maintenance Guide for a thorough look at everything you need to know.

Do you have questions about pool brushes, other cleaning tools, or how to plan for fiberglass pool maintenance? Connect with an independent Thursday Pools dealer near you. They can walk you through best practices, answer your questions, and help you brush off concerns and enjoy your pool with confidence.

How Much is the Smallest Fiberglass Pool?

Posted on October 14, 2022June 11, 2026 by kristin

We can’t read minds, but chances are that if you landed here by searching “How much is the smallest fiberglass pool?”, you are interested in both a small fiberglass pool and are concerned with costs. In this post, we’ll define small fiberglass pools and address some cost-related questions.

About Small Fiberglass Pools

Many fiberglass pools are over 600 square feet (e.g., more than 37.5 feet long by 16 feet wide). Comparatively speaking, a small fiberglass pool may be under 400 square feet. This size will fit into many smaller yards, take up less space, and is still fun and functional. To give you an idea of what that looks like, here are some Thursday Pools small fiberglass pool designs and their dimensions:

Small Fiberglass Pool Prices

Our general suggestion for getting a rough ballpark estimate for our fiberglass pools is to multiply your linear square feet by $1500. Of course, it’s more complicated than that, and you would need to get an estimate from a pool dealer near you to get firm numbers. Every case is different, and fiberglass pool prices vary according to a number of factors, including:

Installation Factors Affecting Pool Prices

Ease or difficulty of accessing your backyard
Excavation complications (e.g., rocky or sandy soil)
Permits and variances
Barrier requirements (e.g., fencing or safety pool cover)
Electrical work
Plumbing (especially rerouting septic fingers)
Dirt hauling
Standard pool equipment (filtration system, skimmer and jets, a vacuum head and pole, vacuum hose, skim net, wall brush, thermometer, and chemical test strips)
Additional pool equipment (e.g., pool heater, automatic vacuum system, salt generator)
Backfill
Restoration

Optional Factors Affecting Pool Prices

Landscaping and hardscaping costs
Patio furniture
Ladder
Slides
Mosaic tile
Specialty lighting (such as LED lights)
Water features such as deck jets, bubblers, and waterfalls
Swim jet system or spa features

Are Small Pools Cheaper?

Yes. Generally speaking, small pools are less costly than larger pools. Not only do they save space in your backyard, but they also cost less to build initially due to fewer building materials being used and easier installation. Additionally, they cost less to maintain. A smaller pool requires less water and fewer chemicals and is generally easier to maintain than a larger pool.

Are Fiberglass Pools More Expensive?

Fiberglass pools are inground pools that are more expensive than above-ground pools. They are typically more expensive than a vinyl liner pool, but according to Home Guide, a fiberglass pool is generally 10 to 20 percent cheaper than a gunite pool. Additionally, fiberglass pools cost less to maintain than traditional pools. Over the course of 10 years, a fiberglass pool will save you 75 percent on maintenance costs as opposed to a concrete pool.

How Much Does a Fiberglass Pool Cost?

Fiberglass pools range from $45,000 to $85,000 on average, but smaller pools may run less. Use the Thursday Pools Pool Cost Calculator to get an estimate for your pool project based on size and desired options. This tool can help you better understand the cost breakdown behind your pool.

Whether you are looking for a small fiberglass pool because you have a small backyard or you are trying to save money, our best advice is to let us get you in touch with an independent pool dealer in your area. A pool dealer can give you the best estimate based on all the factors that affect pool pricing and can answer your project-specific questions.

What is the smallest fiberglass pool size?

Posted on October 14, 2022June 11, 2026 by kristin

Inground fiberglass pools create a unique aesthetic for the backyard, but homeowners with smaller backyards often think they don’t have room for the more elegant option. Fortunately, more options exist in small fiberglass pools than ever before. This post will answer “what is the smallest fiberglass pool size?” and other common questions for homeowners with smaller yards.

What is the smallest inground pool size?

Before answering the primary question of this blog post, let’s first give you some context. We generally categorize an inground pool as “small” if it measures 400 square feet or less. Depending on the dimensions, a small pool can be used for soaking, wading, swimming laps, or incorporating water features.

What is the smallest fiberglass pool size?

While pool manufacturers’ all develop different pool designs and sizes, Thursday Pools has several different small fiberglass pool designs, with the smallest being a wading pool that is nine by nine feet. Here are some of the smaller fiberglass pool designs (under 400 square feet) and their measurements:

Thursday Pools Pool Design	Dimensions	Square Feet
Wading Pool 1	9′ x 9′ 1’6″	81 ft2
Pearl	15′ x 25′ 3’9″	375 ft2
Sea Turtle	9.5′ x 19.5′ 4’6″	185.25 ft2
Aspen (also comes in four larger sizes)	12′ x 25′ 5’1″	300 ft2
Titus	12′ x 26′ 5’5″	312 ft2
Cathedral	14′ x 33′ 5′	462ft2
Lil Bob	13.5′ x 27.5′ 4’6″	371.25 ft2

What is a cocktail pool?

A cocktail pool is another term for a small pool that measures under 400 square feet and is approximately four feet deep. In fiberglass cocktail pools, you’ll find built-in beverage and wrap-around benches that provide places to soak and socialize. It’s a veritable cocktail party in the pool.

What is a plunge pool?

Plunge pools are also small pools but often deeper than cocktail pools. While cocktail pools are shallow and commonly used for relaxing, plunge pools are deep enough to allow for more activity, such as exercise and playing games. However, they may not offer wide-open swimming for a group of people. Plunge pools can also serve as a focal point for socializing.

What is the smallest pool you can swim laps in?

You don’t need an Olympic-size pool to swim laps. Even with a small pool, getting a few laps in is possible. Some small pools can be equipped with strong jets and pressure currents that create a flow of moving water. Activating these features allows you to swim “laps” without actually moving.

What to consider when buying a pool for a small backyard

Local building restrictions

Clearance restrictions may apply between the pool and your home and property lines. Zoning regulations and HOA restrictions can also impact pool size and layout options. An expert pool contractor will be familiar with federal restrictions and local requirements pertaining to your pool.

Amount of space

As a guideline for your own comfort, limit your pool size to not exceed 25 percent of your yard space. For example, a pool should not exceed 24 feet long by 12 feet wide for a lawn that measures 1,200 square feet or less.

Best pool for your needs

One of the most important considerations is how you plan to use your pool. A wading pool may be just what you need for a beautiful aesthetic and relaxation. If you are entertaining, you may want a deeper pool with plenty of seating or a flat-bottom pool for playing games. Another essential factor to consider is other backyard activities and the space required. Do you need open lawn space for play? How much patio space will you need?

The best small pool for you

Choosing a pool is personal. If you’re uncertain about which pool is best for your backyard, try out our pool selector tool as a starting point, or let us get you in touch with an independent dealer near you.

The Lowdown on Tanning Ledges

Posted on June 27, 2022June 11, 2026 by kristin

If you’ve been researching fiberglass pools or have spent time in one lately, you might have discovered the beauty and versatility of a pool tanning ledge. The tanning ledge is a feature, usually as wide as the pool or about nine feet in diameter if inset, that pulls the deck experience and pool experience together. Rather than going back and forth between a deck chair or lounger, you can bring the lounger into the pool! This post will answer the most common questions about pool tanning ledges.

What is a tanning ledge, and why would I want one?

Tanning ledges are an elevated pool bottom for easy entry or lounging. The depth is about 18 inches from the lip, and the water depth is typically around nine inches but can range between six and eight. It’s deep enough that you can cool off but shallow enough that you can place a chaise lounger on it, and it won’t float away. In addition to the feeling of luxury that comes with stretching out and relaxing on the tanning ledge, the feature provides easier entry and exit for parents with toddlers, people with pets, or elderly swimmers.

Tanning ledges offer pool-goers of all ages the best of both worlds. For small kids, they are the perfect spot for them to play and still stay well within your sight. For older kids and adults, they’re great for staying cool while relaxing in the sun. Additionally, they’re great for old guys and gals (and pets) to get in and out of the water without navigating many steps.

What are some other names for tanning ledges?

Have you ever been down south, someone offers you a Coke, you say “yes,” and then they ask, “what kind?” The same way you may ask for a “coke”, “pop”, or “soda” differently depending on where you are, the tanning ledge has its own regionally accepted names.

Are tanning ledges the same for all pool types?

No, you’ll want to consider several factors if a tanning ledge is a feature you want in your pool. When considering a pool tanning ledge, cost, appearance, safety, durability, comfort, and maintenance may influence your pool type choice. While we are fiberglass pool manufacturers, we have a broad perspective based on conversations and working over the years with homeowners, installers, and the innovators in our manufacturing facility. Here is a quick guide to tanning ledge options for vinyl liner pools, gunite pools, and fiberglass pools to help you decide the best pool for you.

Vinyl liner pools

Today’s vinyl liner pools can offer many different configurations with ledges, steps, corner seats, benches, and wading depths that at one time were thought to be impossible. So, if you feel like a vinyl liner pool is for you, a tanning ledge is possible. Here are some factors you may need to consider::

Durability. Often a sunbather’s favorite part of a tanning ledge is the ability to put a tanning ledge chair or ledge lounging chair on it for maximum water-to-sun relaxation potential. There is a possibility for furniture to puncture or tear the liner, so keep that in mind as you consider your options. Safety. Another concern with a tanning ledge on a vinyl liner pool is vinyl’s potential to be slippery. If you’re looking for a tanning ledge as an easy landing pad for pool entry and exit, you should consider slip and fall possibilities, and this goes for all pool types. Water weight. Depth of water is crucial to hold a vinyl liner in place. The shallow water of a tanning ledge area may not carry enough weight to keep your liner in place over a tanning ledge. It can be challenging to get the corners to pull in without ballooning or wrinkling.
Cost. Some buyers go with vinyl because of its comparably low up-front cost. Adding a feature like a ledge can negate some of those savings.

Gunite (concrete) pools

If your budget is unlimited, then the sky’s the limit for how you can configure the shape and size of your tanning ledge on a gunite pool. Gunite pools are entirely customizable. If you feel like gunite is the pool for you, here are some things to think about when it comes to installing a tanning ledge in a gunite pool:

Expense. Gunite pools are incredibly durable, so there’s very little chance of damaging the pool surface with ledge loungers. However, gunite pools can be expensive in the Midwest and may exceed the budget for many homeowners.
Maintenance. There can sometimes be problems with plaster finishes, and in climates that require winterization, the tanning ledges should be tiled or painted (so make sure you consider that when you’re planning).
Surface comfort. You may not have to worry about slipping if the ledge is textured. However, a textured finish could be rough on your feet or your pet’s paws. It can also cause snags on swimsuits for those who sit on the ledge itself.

Fiberglass pools

A fiberglass pool with a tanning ledge may be your best bet. Fiberglass pools have come a long way over the years and now come in many sizes and configurations that include tanning ledges. Here are some things to know about them:

Low-maintenance durability. Thursday Pools fiberglass pools with tanning ledges are structurally very sound thanks to our innovations in fiberglass pool manufacturing.
Affordability. Particularly in the Midwest, a fiberglass pool with a tanning ledge may be less expensive than a custom gunite pool.
Non-slip (and still gentle on feet and paws). The surface of a fiberglass pool is a non-skid gel coat finish that’s the ideal combination of beauty, durability, and smoothness. Of course, everyone needs to be careful when entering and exiting the pool, but fiberglass offers comfort and safety combined.

Are design options limited for a fiberglass pool with a tanning ledge?

While we have to acknowledge the near-infinite customizability of gunite pools, we also must point out that there is a fantastic array of design choices available if you’re looking at an inground fiberglass pool design with a tanning ledge. The choices include freeform pools as small as 25′ in length to a 40′-long rectangle pool with a tanning ledge. Another fun design option, a Wet Deck, has a tanning ledge as a stand-alone complement to your pool. The deck can feature design elements like rocks, tiles, waterfalls, or spillovers.

Thursday Pools Tanning Ledge Options

The more you investigate tanning ledges, the more seriously you might be considering one in the pool you select. We don’t blame you! It’s the perfect luxury-style feature for a fiberglass pool that offers durability, affordability, and safety. Let us connect you with a pool dealer near you.