White Coating...Gel Coat Failure or Something Else

jereece

Member
Jun 19, 2019
8
Charlotte, NC
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.
 

Attachments

  • 20210616_165941.jpg
    20210616_165941.jpg
    179 KB · Views: 8
  • 20210618_201000.jpg
    20210618_201000.jpg
    93.9 KB · Views: 6
  • 20210713_162840.jpg
    20210713_162840.jpg
    434.9 KB · Views: 7
  • 20210713_162853.jpg
    20210713_162853.jpg
    397.9 KB · Views: 6
  • 20210713_163119.jpg
    20210713_163119.jpg
    192 KB · Views: 7
  • 20210713_163150.jpg
    20210713_163150.jpg
    268.3 KB · Views: 7

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
33,391
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
You might want to read my thread.

 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
18,467
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
… 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.
 
Last edited:
  • Like
Reactions: Texas Splash

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
33,391
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
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.
 
  • Like
Reactions: JoyfulNoise

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
18,467
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
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.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
33,391
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
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

Member
Jun 19, 2019
8
Charlotte, NC
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.
 
  • Like
Reactions: Texas Splash

Enjoying this content?

Support TFP with a donation.

Give Support