Salt Water Fiberglass Pool Q&A

Salt Water Fiberglass Pool Q&A

Fiberglass pools are increasingly being chosen by new pool owners over more traditional vinyl liner pools and when you look at the facts, it’s not hard to see why.

Here is a salt water fiberglass pool Q&A with questions and answers to some of the most common queries regarding this popular pool style.

Can you use salt water in a fiberglass pool?

A salt water chlorination system is a popular and solid choice for a fiberglass pool. Fiberglass holds up very well to salt water which helps to explain why boat manufacturers have built them with fiberglass for decades, really dating back to the 1960s in earnest.

Fiber-reinforced plastic (FRP) as it’s also known quickly became a go-to material for boat builders due to the durability of fiberglass and its ability to withstand salt water certainly more so than aluminum. These benefits transfer over to salt water fiberglass pools too.

Are salt water fiberglass pools prefabricated?

Fiberglass pools are prefabricated at the manufacturer’s site and then delivered in one piece to your home for installation. The salt chlorination system, pump, heater, etc are then installed as part of the build just as with any other pool. You can typically use the same products for your fiberglass pool as with other pool types.

While pool companies offer fiberglass pools models off the rack so to speak, you can also add various options to your chosen model or you can build a custom fiberglass pool to your own specifications, at a higher cost of course. In each case, the model you choose is delivered to your home for installation already built. This is very different from a vinyl liner or concrete pool which are built on site in your backyard.

In terms of how the pool is actually delivered, assuming you live in an area with houses on both sides of you, the fiberglass pool shell will be lifted over your house with a crane and lowered into the ground into the hole that has been already been dug, just like in the main photo at the top of the page.

Are salt water fiberglass pools better than salt water vinyl pools?

Fiberglass and vinyl liner pools each have pros and cons so it depends on who you ask. The downside of a vinyl pool is that the vinyl can rip, tear, bleach, leak and will eventually need to be replaced. Vinyl liners can also pull away from the wall of the pool and water can get behind it.

Occasionally the liner can bunch up and wrinkle which may just be a bit of an eyesore (I’ve experienced that and didn’t bother doing anything) or it could become quite large and require you to address it.

One interesting benefit of fiberglass pools: The surface of fiberglass is non-porous and smooth so algae cannot attach itself as it can with a concrete pool.

On the other hand, vinyl pools tend to be cheaper to install so the up front cost is lower. Since most people will tell you that a vinyl liner may have to replaced anywhere from 5 – 15 years after installation, there’s that to consider. My vinyl liner is 11+ years old and is still in fine shape.

A fiberglass pool may last 25 years by comparison although cheaper ones may need to be resurfaced after 10 years (more on that below).

How long do salt water fiberglass pools last?

Fiberglass pools are very durable and good quality brands can be expected to last up to 25 years when properly installed and maintained. As with other pool types good water chemistry balancing is important.

How you take care of your fiberglass pool also matters. If you have a dog who swims in the pool, sharp nails can scratch the finish on the fiberglass. Fiberglass pools have a gel coating which can wear away over time if water chemistry isn’t maintained or if you use harsh chemicals.

With a salt water pool it’s important to remember that salt is corrosive and while fiberglass stands up well to it, metal ladders and other components of your pool can be damaged if salt levels are too high.

Can salt water fiberglass pools crack?

Hairline fractures can occur in fiberglass pools. If the gelcoat is applied by the pool manufacturer too thick, it can crack over time. If the pool is damaged through misuse or lack of care, it can crack as well.

Cracks may also occur if your pool settles and moves or was simply not installed correctly and has shifted.

The surrounding water pressure can also impact a fiberglass pool’s ability to withstand cracking. If the pool is drained too quickly, pressure from the surrounding soil can press on the shell and cause cracks. A major event such as an earthquake or other ground-moving caused by severe rain or drought can also cause cracks in a fiberglass pool.

And if the fiberglass pool is of poor quality and was simply built cheaply, cracks can develop over time.

Can a crack in a salt water fiberglass pool be repaired?

Depending on the size and location it may be something that requires you to drain the pool to fix. Of course, you may not actually be able to see such cracks when a pool is full of water so it may not be something you even notice immediately.

Small spider cracks might not be anything to worry about but larger structural cracks are ones that should be repaired specifically by a pro who has the skill to do so. When it comes to properly repairing a damaged fiberglass pool and also matching the coloring, you’re best to get a professional to do the work.

For serious cracks that are 0.5″ deep and 1″ in length or greater, the area might need to be sanded first before being refinished so you’re definitely talking about a professional job at that point.

Online reports suggest that an average gelcoat repair for a fiberglass pool runs $300 – $400 but for repairs involving repainting the cost could be as high as $800. That’s not including the cost of draining and refilling your pool water and rebalancing the water chemistry.

Do fiberglass pools need to be resurfaced?

Some fiberglass pools may need to be resurfaced after around 10 years. While higher quality fiberglass pools that are well maintained may not require it, lower quality pools that are not properly maintained and balanced (water chemistry is what we’re talking about here) may lose their gelcoat which is the actual surface of every fiberglass pool. It’s the colored resin that you see on the pool and covers the pool shell.

The gelcoat is a liquid that is sprayed on over several passes to a thickness of about 25 mm – 30 mm. It has to be balanced to be thick enough to protect the structure but too thick that it cracks nor too thin that it blisters and exposes the inner surface. In other words, it’s an important job done only by a professional.

Can salt water fiberglass pools be heated?

Fiberglass pools can be heated using the same heating options as any other pool. Adding a salt water chlorination system doesn’t change things. The same pool heating options for a regular chlorine pool that is vinyl or concrete can be used by a salt water fiberglass pool.

Natural gas-heaters remain the most commonly used heating option although heat pumps and solar options are becoming more widely available. If you live in a very hot environment, you may skip the heater altogether and rely on the sun to heat it in which case you may want to invest in a solar blanket.

What are the advantages of a salt water fiberglass pool?

  • Very durable and algae resistant surface that holds up well to salt water.
  • Long lasting: A quality fiberglass pool may last up to 25 years or longer with some claiming a lifespan of up to 40 years.
  • Available in a wide variety of styles, shapes and designs.
  • New models are high quality and professional looking with very interesting color patterns to choose from.
  • The stairs and seating can be built in a matching color offering a more integrated look than a vinyl pool that uses white plastic steps that are very visible and stand out.

What are the disadvantages of a salt water fiberglass pool?

  • More expensive up front cost than a vinyl pool installation. An average fiberglass pool install is around $45,000 but can be lower for smaller pools and higher for larger pools with more features.
  • Fiberglass can crack and fade and may need to be resurfaced over time if not properly cared for.
  • Installation is very important and must be done correctly to avoid shifting or other problems down the line.
  • Fiberglass can be a bit slippery when wet so care needs to be taken when walking in and out of the pool.

Salt water fiberglass pools install examples

I own a salt water vinyl liner pool so that’s the experience I have. My next door neighbors got a salt water fiberglass pool built as did neighbors across the road. They had very different styles of pools installed.

My next door neighbors installed a fiberglass plunge pool in their backyard with a Hayward salt water chlorination system. They have the same sized backyard as us but as they have a large dog, they wanted to have some grass and backyard area left. Since their kids are already teenagers and will probably be moving out in the next few years anyways, a smaller plunge pool for wading and paddling around in suited them just fine. They also had patterned concrete installed around the pool area which looks very nice.

My neighbors across the road got a larger fiberglass pool installed also with a Hayward salt water chlorination system and gas pool heater. Because their backyard is sloping downwards, there was much more work and cost involved in this install since a retaining wall also needed to be built. They additionally got a water feature around the pool installed, a concrete patio poured around the pool and also got a splash over feature. Basically two bathtubs at the bottom of the downward slope that water drains into.

The water feature is pretty cool. It’s a series of water jets that spray back into the pool all around the concrete patio. I think if they had to do it again, they’d skip the splash over feature as the bathtubs routinely get very dirty and on at least one occasion, a large rodent fell in and drowned. Of course, that’s a hazard that anyone with a pool could face and generally will from time to time.

In each case, my neighbors chose a very dark blue color for their pool surface which looks really high quality and professional. It hides dirt too. In my pool the standard light blue liner has been bleached a bit over the years from the sun and it does not hide dirt or algae at all. It makes it very to see all dirt and debris.

Carl Mueller

I bought a home with a salt water pool in 2006 and soon realized the benefits over traditional chlorinated pools. On this website I'll discuss all the tips and tricks I've learned over the years. I'll also help you troubleshoot various problems with pools in general and ones specific to salt water pools that I've experienced personally!

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