Fiberglass Faded & Chalky - Proper Levels?

[poolheaven17]

Moved from HERE.

I have experience with this issue as I found my 2 year old pool had faded and was not as glossy below the water line last spring and I thought this could be the reason. I was following the TFP pool water chem stats and I will admit not that well during winter of 2018. I had left my SWG on as a source of chlorine and there were days that it was running 24/7 with the pump due to freezing temps and although I put it at 5-10% production I was not checking the chlorine nor PH throughout this 1-2 month period and assumed that I could get it all in order upon warmer weather. Having had my pool for over a year and really just concerned with PH, to the 7.0-8.0 and chlorine level high enough with CYA I always tended to the higher side of chlorine, shooting for 5 .0 but ending up closer to 6-7. My calcium and TA were in range during the season with TFP standards. Upon this fading I went into full research mode. I did not trust the manufacturer because of others' experience on here and my pool installer said he had not seen the situation. I believed him and still do because he had proven to be a man of great integrity throughout our install and always followed up with issues. He sent his tech who has maintained all types of pools for 25 years out immediately. She gave me the manufacturer recommended balance numbers with CH 350-400, TA 80-120 and said she had never had the issue with clients she had trained for these numbers. She said she never got above 5.0 on CL. There had also been issues with over doses of chems in our pool early on due to miscalculations of water so I have no 100% reason. I just know that when I started noticing issues my numbers were Cl 6.5, PH 8.2, TA 60 and CH 157, CYA 70. Other than adjusting the ph, TA to compensate and possible CH a little, those numbers would have been pretty typical for my pool. When I went to the pool store in distress they said get TA up and no worries with CH because = fiberglass pool and wouldn't even sell my calcium without a water sample when I told them I wanted to get it up to 350-400 based on manufacturer's recommendation! Last time I went there but I digress.

I called the resource I used to decide on a fiberglass pool, former rep for my manufacturer but no financial interest in my situation and he has since gone on to manufacture his own brand of fb pool. He is also on a board of fb pool manufacturers associations. He stated that if my numbers were that during the winter with the ph as high as that and possibly higher with the SWG on constantly the pool could fade in a matter of a couple of weeks and that that high CL over a few months with other chems in balance could fade the pool. It was his opinion over 5.0 CL on a regular basis based on experience, but his FB manufacturers would say 3.0. He first recommended getting CH manufacturers guidelines because the calcium acts a buffer as well as alkalinity I also saw on here that helped one person's situation so I did that. In the process of research I even called a scale expert in Australia to see if I could get a test from him to see if it was scale. While he could not ship products, I talked with him at length. He stated in Australia, almost 80% of pools are fb and have SWG. He said my normal CH level would be unheard of there where they are closer to 1.0-2.0 and we agreed his area is very similar to my TX climate. When I explained the CYA chlorine situation and how it would be impossible for those levels with 70-80 CYA, he said most people there do not use CYA BECAUSE SWG are constantly adding CL and very small amounts kill pathogens quickly with no CYA. He advised to the let the CYA burn off and have no more that 3.0 of free CH in the pool at any time, shooting for 2.0. It was within the TFP guidelines for CYA of 30 so I decided to try and just let my CYA go down and adjust target CL levels with normal drains with rain and slight reduction of water when I needed to add anyway. This was in May 2019 and while I do test my pool every day, very rarely did I have to adjust any chemicals frequently other than PH and once every couple of weeks for TA to be 80-90, keeping FC levels to 1.5-3.0 and CC never above .5. I never had to shock the pool, and it stayed just a clear as ever, although with the higher CH it does not have the very light soft feel. This is a small issue compared to damaging the gel coat further. Since then the fading has not gotten worse and the glossy feel got better so I am assuming there was some scale or the calcium helped seal the finish. I had the water recycled at the beginning of the season this year, leaving almost 0 CYA and have noticed great volatility in chlorine numbers , but never to the point of having CC go beyond .5 or algae problems. For this reason I did add CYA to 20 just to help with balancing after recycle. That might be the level that works with keeping the FC level down , agrees with TFP chlorine levels and for now, I don't see a downside except the difficult test in my opinion.

I am still in experiment mode but so far, so good and both very experienced consultants attest that with these numbers my pool coating will look the same 10-20 years from now and incur no further damage. It is my belief that the prevalence of CYA use is for people to be able to have a pool maintenance contractor check levels once per week and shock the pool if needed frequently. I would never be comfortable with that and it appears that it is not conducive to the FB SWG combination at all. In the end, the FB manufacturers recommended chem levels seem to be more important in a FB pool as it is a lot easier to correct plaster finish that FB.

I realize there will be people whom will disagree and I readily admit this is experimental but having combed this forum for 3 years, I am seeing time and time again fading and chalking issues with new FG pools and I am looking for actual success stories with the longevity of FB pool finishes and the few people I have consulted have these successes on a REGULAR basis. They have no financial interest to tell me otherwise and I am choosing to trust them. I still value very much the information here and appreciate this site for giving me information in order to take my pool care into my own hands. I value others' input whether they disagree or not and whether they have had issues or their pools look the same as 10 years ago. We are all doing the best we can to preserve our investment and leisure. Thanks for listening.

 

[Texas Splash]

I would be cautious about some of the info you received from these disinterested individuals. Even the generic pool industry standards, that we see here a TFP as a bit outdated, acknowledges a minimum CYA of 30. Here at TFP, even indoor pools are recommended to have a minimum CYA of about 20 ppm. With a CYA level lower than that or closer to zero as you described, the chlorine is extremely harsh. Much more harsh than a pool with a CYA of 50 and an FC of 8 for example. So the rationale of maintaining such a low CYA and FC seem difficult to accept. In our TX heat, unless someone is adding liquid chlorine multiple times throughout the day, or has their SWG set to run continuously, the chlorine will disappear relatively quickly with such a low CYA. That has been proven.

Now I have had the Viking/Latham companies emphasize the need for SWG owners to be careful about excessive chlorine produced, but the examples they illustrated to me were SWG pools with a cover, so chlorine entrapment was said to be the issue.

In my personal case, and perhaps yours as well, the situation is very frustrating. I do believe there are still some unknown issues with the gelcoat of FG pools. But for every FG pool that experienced an issue like us, there are thousands who are maintaining normal chemistry and TFP standards just fine. We just don't see their posts all that often because they have no problem. In the end, we may never know why ours changed. Was it something in the water chemistry? Was it a defective application of the gelcoat? Something else? We may never know. But I would be careful about drastic chemistry changes that are far outside the recommended ranges, especially when it comes to conditioning the water from the harshness of the chlorine (CYA) and keeping the water sanitized (FC). Maybe after a few months or a couple years of various tests one of us FG owners will crack the code on this one.

 

[JoyfulNoise]

Thank you for writing this up. While I appreciate all the researching you have done and people you have contacted, there is a lot of misinformation to correct as much of what has been told to you are "certainties" based on coincidence and not causation. Stating propositions without a scientific underpinning does not make them true simply because an "expert" says so. Evidence is certainly important but one must always have an underlying mechanism to explain what that evidence reveals.

Here are some facts that are missing from all of the information that is presented in your post -

1. Free chlorine, in and of itself, is a meaningless number.

Free chlorine is simply the sum of chlorine bound to the CYA molecule (reserved chlorine) and active chlorine species which, in water, are hypochlorous acid (HOCl) and hypochlorite anion (OCl-). When chlorine is bound to CYA, it can be thought of as "useless" - it has no oxidizing power and no sanitizing power. Hypochlorite (OCl-) anion is a weak oxidizer and weak sanitizer on its own. Hypochlorous acid (HOCl) is a powerful oxidizer and very potent sanitizer and it is the chemical species that is most responsible for keeping water clean and sanitary. It is hypochlorous acid that oxidizes organic compounds and it is hypochlorous acid that attacks biological organisms (bacteria, algae & viruses) and destroys them. Therefore, it is hypochlorous acid concentration that matters the most for pools.

The problem is, there is no simple and easy way to only measure HOCl. When CYA is present, over 95% of the chlorine in the water is bound to CYA and the rest splits up into hypochlorite anion and hypochlorous acid based on pH. When the pH is 7.5, HOCl/OCL- is basically 1:1 ratio. So let's use your real life example from the Australian fellow (pH is set to 7.5 to make an apples-to-apples comparison) -

Your water - pH 7.5, CYA 70, FC 5ppm

HOCl = 0.029ppm or 29 parts per billion

Australia recommendation - pH 7.5, CYA 0, FC 1ppm

HOCl = 0.484ppm or 484 parts per billion

So, if you follow the recommendations of the Australian guy (which you should not), then his water has 16.6 times as much hypochlorous acid in it then your water does. Hypochlorous acid is the chemical species that is going to most damage a gel coat. So, if his water is 16 times as oxidizing as your water, does it make sense that his FG pool surface will fair better than yours? His argument makes no sense.

Also, one has to take his recommendations with a grain of salt - the reason why Australians don't have a lot of CYA in their water is not because they care about their pool surfaces, it's because their public health codes don't allow the use of CYA in commercial/public pools. There is great misunderstanding surrounding the role of CYA and the sanitizing power of chlorinated pool water with the misconception that CYA makes water less sanitary. That's only true when the free chlorine (FC) is kept constant but the CYA is allowed to vary - we see that all the time in over-stabilized pools. When the CYA is high and the FC is kept at industry recommended levels, algae can easily grow because there isn't enough HOCl in the water to kill it. When you vary FC with CYA and keep the ratio constant, the HOCl level stays the same and you can dial in whatever sanitizing power you want because you can easily fix the FC/CYA ratio to whatever value gives you the correct results (clear and clean water). And, because CYA captures and holds most of the chlorine in reserve, the water is much less harsh on skin and bathers because the reaction rates are much lower. This would also hold for polymer surfaces as well (like pool toys and gel coats) - with a stable and low level of HOCl around, polymer materials will last longer.

Which brings me to the next point -

2. Gelcoats are polymers (organic compounds) and not all gelcoats are created equally

Ask any fisherman with a fiberglass boat and they will tell you that the one thing they spend most of their time worrying about is how good their fiberglass surfaces look (that and the size of the fish they just caught). And, when you wear a black rubber-soled sneaker onto a boat and leave a black scuff mark on the gelcoat, most boat owners will want to string you up from the mast for ruining their fiberglass surface....I know, I did that once to a boat owner and he almost made me walk the plank. Gelcoats are delicate things and they are easily damaged because they are there to protect the fiberglass. In the situation of a boat, you can clean and polish the gelcoat as well as repair it in a lot of circumstances. In a submerged pool surface, a fiberglass gelcoat can not be easily repaired or fixed.

But what is a "gel coat" ? The gelcoat on a fiberglass surface is essentially a clear epoxy resin that is there to maintain surface integrity and keep the glass fibers in the layers below from contacting a person's skin. The gelcoat, by design, is meant to take all of the wear and tear so that the actual fiberglass structure remains intact. It is, by design, a sacrificial coating. Good pool manufacturers know this and they try to tune the properties of the gelcoat to be as resistant to chemical attack as possible so that the surface maintains its smoothness. However, like all resin materials, they will breakdown over time from exposure to water, sunlight (UV), heat and chlorine...it is inevitable. All polymer materials undergo a process of hydrolysis (water reacting with carbon-carbon bonds and breaking them down) and that process can be greatly influenced by heat, UV and presence of other oxidizing species. UV light in particular can interact with chlorine and form very powerful oxidizing compounds known as free radicals (hydroxyl radicals, oxygen radicals, chlorine radicals, etc). Radicals are even more powerful oxidizers than ozone (O3) but they are short-lived species. When a gelcoat is submerged in chlorinated pool water, it is subject to same chemical attack as any other organic compound and, over time, will become more porous and rough. What many people think is "scale" on their pool walls is actually nothing more the microscopic porosity that has developed which gives the clear gelcoat a hazy look. When you sand the gelcoat with a fine grit paper, as others have done, you remove a lot of that hazyness and expose a fresh layer of gelcoat. This is not unlike how you can polish fine scratches and swirls out of an automobile's clear coat - the clear coat functions as a protective sacrificial layer that you can finely sand and polish back to an original shine. But, you can only do so much polishing of a clear coat before you'll hit the underlying paint. At that point, the clear coat needs to be restored in thickness. Fiberglass gelcoats are the same and, after enough degradation, a fiberglass surface needs to be sanded down, the fiberglass needs to be patched if there are exposed fibers and then a new gelcoat has to be applied.

Pool manufacturers can apply their gelcoats by any number of processes but the good ones know to use the correct materials and thicknesses to make a gelcoat last. Other manufacturers may not be as careful. They all tell you that fiberglass surfaces are "chemically inert" and give the pool owner the false impression that they need very little maintenance, but that is simply marketing hype. All pool surfaces, no matter the type, need maintenance and wear out over time. Vinyl needs to be replaced, plaster needs to be chipped out and reapplied and fiberglass gelcoats need to be redone. And just like plaster and vinyl, these surfaces come from many different manufacturers with lots of variance in materials and methods of manufacturing. There's more than enough variation in those processes to allow for pools that will seemingly last forever and those that start to degrade within years. The industries that make these materials LOVE to put the onus on the pool owner and blame them for any issues and they write their warranties in such ways that they will almost never have to honor them. Their chemical recommendations make no sense and they typically have no proof of why they recommend a particular level other than "In all my years as a _____ manufacturer, I've never had a problem...." That's not proof, it's anecdote and anecdote is not data.

Let me end this by saying that it is your pool and your pool surface and you can follow whatever pool care regimen you prefer. The advice on this forum is as science-based as we can possibly make it and, as Pat said, for every post about a hazy fiberglass surface, there are probably two FG pool owners that never have a problem. I truly believe you simply got a pool with a poor quality surface that is not your fault or, even dare I say, the manufacturers fault per se. The industry must make tens of thousands of pool shells per year and no manufacturing process is 100% perfect. It would be nice if they honored their product by replacing defective pool surfaces without making the pool owner out to be problem, but they'd rather put that onus on the pool owner. Not much you can do about it.

Best of luck to you.