White Coating...Gel Coat Failure or Something Else

[jereece]

In May 2020, I had a new fiberglass pool installed, so this is the second summer of use. It uses a salt cell for chlorine and cartridge for filtration. I live in North Carolina. Water chemistry results below.

At the beginning of this second pool season, I had a lighting issue that required my pool installer to lower the water a couple feet. It was then that I noticed a white coating on the pool wall. As I looked around in more detail, it's mostly an even coat, but at some points it's a streak. See attached photos. My initial thought was calcium, but my pool is very low in calcium and the makeup water is also low in calcium. When I rub my fingers across it, the white residue does not come off. I put a drop of muriatic acid on one spot and it did not bubble or dissolve the white substance. I tried to manually remove it using gentle buffing with a Scotch-Brite Non-Scratch Scour Pad, but that did not remove it. I tried a gentle auto compound, but that does not remove it either. My pool installer put a couple bottles of calcium scale remover in the pool, but even after weeks that did not help. My pool installer said in the 20 years he has been maintaining pools, he has never seen anything like this before. So I am beginning to wonder if this is a failure of the gel coat, but wanted to enlist the opinions of someone more experienced.

FC: 2
CC: 0
TC: 2
PH: 7.4
Hardness: 75
TA: 60
CYA: 30

I appreciate your thoughts and any recommendations.

 

[Texas Splash]

You might want to read my thread.

Fiberglass Discoloration (Faded & Chalky) - My Story

DISCLAIMER The following is a dialog of my own personal experience. Any processes used, chemically or otherwise, were performed strictly on my own without any recommendations from Trouble Free Pools. FUTURE POSTING I am trying to keep this thread streamlined with just my own progress for all...

www.troublefreepool.com

 

[JoyfulNoise]

… My pool installer said in the 20 years he has been maintaining pools, he has never seen anything like this before.

That’s pool builder speak for “your problem, not mine. Please leave me alone …”. I sincerely doubt that if he’s been in the business as long as he says he has and he installs fiberglass that he’s not seen that before. It’s not a gel coat failure, it’s simply gel coat aging. The fiberglass is submerged in water 24/7/365 with a potent oxidizer (chlorine) and sun shining on it all day long. The gel coat is nothing more than a thin epoxy finish that is colored blue. As the gel coat hydrolysis (breakdown) happens the surface goes from smooth to microscopically rough and light is scattered more diffusely rather than reflected. This makes the surface look “chalky”. If the chosen color was applied to the gel coat and not all the way down into the fiber resin, then the color will slowly bleach out as well. Blue is especially difficult because blue organic dyes fade very easily from UV light.

You can test the gel coat in a discrete area by sanding it using a very fine wet/dry sandpaper. I would suggest a very fine grit like 240 or finer and test in a small, inconspicuous area. If the sandpaper restores the surface finish then you either have to live with the pool as-is or pay for someone experienced in fiberglass restoration to brace, drain, and restore the entire pool surface. That won’t be cheap and you’d better find a pro to do it or else you will be left with a mess.

Sorry, but this is life with fiberglass, it’s not the perfect surface pool installers market it to be.

 

[jereece]

...it’s simply gel coat aging.

So a gel coat can age enough to discolor that bad in only 12 months?

 

[Texas Splash]

So a gel coat can age enough to discolor that bad in only 12 months?

They age a different rates based on sun exposure and chemical maintenance. Mine took about 3 years to really notice something changing. 12 months seems a bit quick IMO. If you contact your installer and/or the manufacture, you can bet they will blame any such changes on poor chemistry. I suspect they will also point at teh SWG trying to claim it, along with pH, accelerates the oxidation process. Total craziness. I have next to no doubt that will be there position. As Matt noted, changes are inevitable. I think another wildcard factor in all of this might be the gelcoat quality and application process. Variances in production might also contribute to changes we see, but there's next to no way for us to prove that. You can try to push the manufacture for some warranty assistance. There have been a couple TFP FG owners who had success getting their pools re-coated. In one case, I know it started doing the same thing right after the whole process.

 

[JoyfulNoise]

As @Texas Splash says, you can try a warranty claim but, based on what you have posted, the manufacturer will almost certainly say that your water was too aggressive (CH/TA/pH too low resulting in a low saturation index) or your SWG was the problem. And, even if they did agree eventually that the gel coat was aging/fading too quickly, their solution would be to drain the pool and sand the gel coat down but not before they have you running in circles for months attempting all kinds of chemical treatments that won’t work.

 

[jereece]

Has anyone ever tried this product? Pool Stain Removers | Trusted Experts in Swimming Pool Stain Removal

 

[Texas Splash]

Your pool your $$$ as we always say. But that product appears to be another spin on a no-drain acid wash. What are those for?.................. calcium scale. You already know it's not calcium (just like my top step testing) since undiluted acid did not fizzle. I doubt you will see any improvement, but it's your call. If you do attempt a product like this or any other, be sure to watch your existing chemical levels closely as these products can cause a bit of a shift in chemistry.

 

[jereece]

Your pool your $$$ as we always say. But that product appears to be another spin on a no-drain acid wash. What are those for?.................. calcium scale. You already know it's not calcium (just like my top step testing) since undiluted acid did not fizzle. I doubt you will see any improvement, but it's your call. If you do attempt a product like this or any other, be sure to watch your existing chemical levels closely as these products can cause a bit of a shift in chemistry.

My pool manufacturer sent it to me to try for free, but the pool cannot be used for 7 days. So after the swimming season is over, I will give it a try. If this does not work, then this will be more evidence that it's a gel coat problem. Since this happened after only 12 months, hopefully they will cover it under the warranty. But time will tell.

 

[Texas Splash]

Good luck and let us know how things go.

 

[jereece]

I have an update on the problem with the white coating on the surface of my fiberglass pool. I finally concluded that the white coating is the result of the pool manufacturer making an initial crack repair immediately after the installation of my pool. The year my pool was installed, it rained a lot. My pool sat in the hole for several weeks cocked at an angle due to all the rain. This caused a crack in the deep end where the wall meets the floor. After the pool was installed, the manufacturer came and sanded the crack, then repaired the crack and recoated that area. The sanding created a lot of white dust that settled out all over the pool. I asked if this should be cleaned prior to refilling and they said no, that it will be removed by the pool pump. But, evidentially it adhered to the pool surface. I came to this conclusion when I noticed a 5-inch circle on the bottom of the pool that was significantly darker blue than the rest of the pool. I looked back at pictures I had taken of the repair and discovered that a small can was sitting in that spot when the manufacturer was sanding. So the white dust did not settle out in that area. I have also determined that auto compound does a good job at removing the white material. So now I am having a conversation with the manufacturer to come back this fall or next spring to buff off this white material.

 

[Texas Splash]

That's very interesting.