White deposits covering Fiberglass pool

dsm1212

Member
May 4, 2017
19
Massachusetts
Just placed an order for fg pool and reading everything i can. One comment here that may be way off base for a pool, but i had something similar in my fg hot tub before I was careful about calcium hardness :-(. Easier to drain a hot tub so I did and was able to try a bunch of different things on it. As I said maybe this isn't right for a pool but I found Bon Ami was like magic. Very little effort just water and a little powder with a couple back and forth motions. I used a magic eraser to do this but I don't know if it was necessary. Maybe what I has was not calcium, I don't know, but it looked like it.

Steve
 

Rose1234

New member
Jun 17, 2017
1
Macomb
OMG - this is exactly the same thing we have in our pool. It must be from the same manufacturer. Would it be possible to redo just the top 8 inches of the pool's gelcoat? I didn't think it was scale as it is not raised and it goes away with a splash of water until it dries again.

One of the stores near our house puts a tile border around the top of the pool, but it is very expensive. If we did decide to do that, what about the rest of the pool. If the gelcoat is shot, then what effect does it have on the rest of the pool? Since it stays wet, it looks fine under the water line.
 

sbv16

Member
Jan 28, 2017
9
Aus
Hi all

I thought Id update this thread given others mentioned they had similar issues.

I drained the pool and took photos of what it looked like with no water.

Undiluted hydrochloric acid did not touch the staining so I guess it was chlorine etching the gelcoat.

https://www.dropbox.com/s/nkn4pq6146juxik/20170301_103036.jpg?raw=1

https://www.dropbox.com/s/zlo4klnetgfcivk/20170301_103038.jpg?raw=1

https://www.dropbox.com/s/640zwcxbt9t4txh/20170301_103021.jpg?raw=1

I ended up sanding the entire surface and buffing with a rotary:

https://www.dropbox.com/s/nxqwn1jd15x6m3b/20170302_135815.jpg?raw=1
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
33,647
Texas, San Antonio/Marion, South-Central Area
Pool Size
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Chlorine
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I'm curious, looking back at your post #11 and pool history, your FC levels never seemed to be too excessive. Neither did your pH, CH, or CSI levels. Did you ever learn anything else from the manufacture about what could've caused this issue? If it was chlorine-related as you suspect, was there anything you can think of that could've contributed to this type of corrosive/etching action? For example, do you have any suspicions that the CYA level was lower than expected thereby not protecting the gelcoat from the FC? Your experience could be a huge learning experience for other FB owners.

Lastly, can you describe a little more the sanding/buffing process (i.e. what grit sandpaper, buffing pad(s), gels used if any, etc).
 

sbv16

Member
Jan 28, 2017
9
Aus
There was a lot of conflicting info provided by both the manufacturer and the pool supply stores.
What was clear though is there are many people experiencing this issue (reading through pool review sites and after being shown photos of other pools with the same issue at the pool supply store).

In the end the manufacturer stated the chlorine levels were too high and above the recommended warranty ranges.

I ended up seeking the advice of pool resurfacing companies who said they see this all the time. They claim this is etching of the gelcoat caused by high chlorine and prolonged use of pool blankets. In my case i used the pool blanket frequently and whilst overseas the automatic chlorinator was over chlorinating the pool. This process happened over time but the worst of it occured in the weeks we were overseas and with the chlorinator pumping too much liquid chlorine in with the pool blanket on.

If you look at gelcoats on 30 yr old pools you can see the color is virtually etched out of the gelcoat by virtue of the danage chemicals cause gelcoat through long exposure. This is that process but accelerated.

As mentioned when the pool was drained undiluted hydrchloric acid did not make any difference so I had to mechanically remove a thin layer of gelciat per the manufacturers recommendations.

It would take too long to wet sand entirely by hand so in my case i used a dual action sander going down to around 300grit sand paper. It is best to wet sand gelcoat not dry sand but in my case I didnt have access to a compressor or air driven sander so I dry sanded. I had to swap sand paper very regularly due to clogging.

After sanding by machine this then cut enough of the material back to allow me to wet sand. I wet sanded at 200 grit, then 400 then 600. When using the machine you have to be careful not to sit in one spot too long otherwise the heat generated causes spider / small hairline cracking.

I then used a foam polish / cutting pad on a rotary polisher with a compound capable of removing 600 grit sand marks. You only want to remove just enough material for the etching to no longer be visible. Givedn the thickness of gelcoat sprayed onto pools you would have to be pretty silly to manage to sand through. Need to be careful though that you dont sand so far that you reveal the speckle in the gelcoat otherwise you will feel the partially exposed speckle when you rub the surface.

This process was not easy and i would only recommend to people who are committed to doing the job, have the tools and some experience buffing gelcoat. A resurfacing company would not do this, they would grind off the gelcoat and refinish completely. As this was a 3 yr old pool I didnt want to do that or pay the considerable cost to do so.

You also need to brace the pool prior to draining although this turned out tok be less difficult than I had imagined.
 

Jezza

LifeTime Supporter
TFP Guide
Jan 18, 2015
994
Bunbury, WA, Australia
That's an awesome job. Very interesting read- got me thinking about my FG pool. Touchwood -my gelcoat still looks as good as the day I bought it. Luckily, I discovered TFP early on and worked out straight up what to do regarding chemical balance.

Interesting theory about the pool cover supposedly being part of the problem-just wondering how that came into the equation??
 

sbv16

Member
Jan 28, 2017
9
Aus
Pool cover was mentioned by manufacturer. I did leave pool cover on sometimes for weeks without removing.

I just dropped by the pool supply store today and they mentioned more and more people have come in with this issue (mainly pools that are 2 to 3 yrs old). Pool manufacturers are blaming high chlorine residue and prolonged use of pool blanket. Note many of the people mentioned at the pool store dont use a pool blanket and some had very good test results but still got the chalking. In my case I had some test results exceeding 2.0 FC which means no warranty for me.

Its also worth mentioning since doing this at the end of summer i also disgarded my automatic pool chlorinator, converted the pool to salt and purchased a new salt chlorinator. I just didnt want to risk it happening again. Iv been testing weekly and religously keeping FC below 2.0.

It looks like some of the chalkiness is returning on the deep side of the pool. I might drain again and inspect in summer. Lucky its a small pool!!
 

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needsajet

TFP Expert
LifeTime Supporter
Jan 4, 2016
4,955
Sydney, NSW, Australia
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Wow, just wow. This totally sounds like a manufacturer using water quality strategies to prevent warranty claims. Even without CYA, 4 ppm FC is allowed in drinking water and there's no warranty sleeze at any level of chlorine for bathtubs, showers, or canoes! What a crock of.
 

Jezza

LifeTime Supporter
TFP Guide
Jan 18, 2015
994
Bunbury, WA, Australia
Yeah totally agree with Jet. I'd be going through the fine print on the contract. I am assuming your chlorine hasn't been ridiculously high without CYA for prolonged periods of time. The pool cover theory also seems ridiculous to me. Unless it's temperature related I dont see how it affects your fundamentalwater chemistry and only perhaps your CSI. I would expect that a gel coat on any of the leading FG manufacturers in Aus should last longer than a couple of years assuming its the gel coat that has been compromised.
 

sbv16

Member
Jan 28, 2017
9
Aus
Even after pool was drained I still thought it appeared like calcium or buildup of water deposits. But it didnt react with acid.... so I dont think it can be calcium?

Another thing worth mentioning is in certain light (especially at night) you can faintly see even in some of the photos previously attached that the colour of the gelcoat below the waterline has slightly changed. Its hard to describe. This is after pool was sanded.

I guess the pool blanket argument is that it traps chlorine which builds up quickly without warning. The other issue with this is pool blanket warranty and pool warranty clearly says do not leave blanket on for extended periods. I thought i was protecting the pool by leaving it on - silly me.

Should also point out on first contact with manufacturer they claimed it was calcium (proven by use of 600 grit removing pproblem) and that the problem could be solved using calcium treatment.

This advice then changed after pohotos were sent through when I became desperate. All the sanding proves is that removal of gelcoat is removing the problem.

I hope others experiencing this in aus see this thread.

I have been wondering though about low hardness levels. All pool supply stores keep telling me this doesnt matter on new fiberglass pools......
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
18,622
Tucson, AZ
Pool Size
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Surface
Plaster
Chlorine
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I think what has to be realized is that this is just the nature of fiberglass surfaces in pools. There is no chemical solution here or anything you could have done differently with your pool water....and I think the FG manufacturers know this and give people the run-around to cover their rears.

Fiberglass is a composite surface made up of an resin layer impregnated with glass fibers or glass mesh and then an outer layer composed of an epoxy and polyester resin with colorants added, aka, the gelcoat. The gelcoat is what is in contact with water and, like any polymer, it will degrade over time as water hydrolyzes the surface while chlorine and UV provide powerful oxidizing agents to breakup the polymer bonds. If you look at a polymer surface that has been degraded by hydrolysis under a microscope, what you'll see in cross sectional view is a thick, bulk layer of the gelcoat that is dense and hard with a thinner, porous and cracked layer on top. Almost all pigments will suffer bleaching from chlorine exposure. This is common to all plastic that have been degraded by exposure to water. When light hits the porous & cracked surface, it scatters in all directions giving the surface a hazy or chalky look. When you sand down the gelcoat, all you're doing is mechanically removing that porous layer and exposing fresh gelcoat material below. Some polymer surfaces are better than other (PVC for instances does not hydrolyze as fast).

Boaters know this very well. They spend countless hours and dollars trying to keep their FG boats looking beautiful. Some even go so far as to restore the gelcoat finish and then add a wax to the surface to act as a sacrificial layer to protect the gelcoat. There may be products that can be applied to FG pool gelcoat surfaces to seal them better when they become chalky but only the manufacturer can tell you if that's an option.

At the end of the day, I think you have to accept a certain amount of chalkiness to FG surfaces, there's just no way to avoid it unless you plan on filling your pool with bottled water and never using chlorine. As for their claims that excessive use of a blanket is the problem, that's baloney. The real problem with the vast majority of pool surfaces (FG, vinyl or plaster) is pool owner negligence when it comes to chemical balancing and the fact that most people rely on the really bad advice of pool stores for maintaining their pools.
 

RunPool

In The Industry
Nov 7, 2018
3
Russia Moscow
Hey. I am from Russia, and I have some information for you. Information about the degradation of gelcoat. I work for a company that sells fiberglass pools made in Europe. We have a lot of calls from buyers whose pools are white. We traveled a lot to look at these pools. One thing is clear, this is not a precipitate of calcium. No acid works with this white formation. We tried different acids. Even those whom nobody tried on pools- concentrated sulfuric acid, nitric acid, acetic acid, formic acid, hydrofluoric acid.
WhatsApp Image 2018-11-07 at 14.54.43.jpeg22.jpg

There are some pictures with whitening. I asked the manufacturer a lot what happened to the pools. He always answered "this is calcium." When I realized that the manufacturer would not tell me the truth, I asked the manufacturer of the gelcoat. They told me that it was probably a badly polymerized gelcoat. But if the gelcoat is not completely polymerized, it will turn white very quickly. A few days in the water and it is already white. I know, I was doing poor repair, it was cold, and the gelcoat did not cure 100%. When poured into the pool water after 2 days where the repair was already white.
 

RunPool

In The Industry
Nov 7, 2018
3
Russia Moscow
RunPool, that is interesting news to hear. Thank you for the information, and welcome to the TFP forum! :wave:
Thanx. So. Then i began to look for a way to fix this problem. I thought - if the gelcoat is degraded, entered into a reaction with water, it can not be corrected or fixed. So it must be removed. But that layer of gelcoat, which we will open when we remove the spoiled one, will also degrade. So it must be protected from water. We have been looking for a means. All types of wax, car polishes and impregnations for stones did not work. More than 1 year only wax remained in the water - 80% bee wax + 20% carnauba wax. It is difficult to apply this alloy, you need to work with an electric heater about 80 Celsius degrees. Now we are testing the resin to cover the tanks in which the acid is stored. It is an alcohol soluble polymer. While my tests did not last more than one year, thats why I can not say that it works or not. Waiting for coming summer. Sorry for my english:D
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
18,622
Tucson, AZ
Pool Size
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Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
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Gelcoat materials are tricky. In general terms, they are thermosetting polymer materials. Typically thermosetting polymers start with a linear chain polymer and a mixture of shorter chain polymers which, when heat is applied, begin to cross link and harden. Once fully cross-linked, they become very hard and chemical resistant. They can not typically be reworked by heating as they simply break down when heated to high temperature rather than melt.

The thermosetting process can be quite slow with just heat applied and so the starting mixture usually has reactive cross linking agents added to it (organic peroxide’s) and sometimes a metal catalyst (cobalt usually which is why gel coats can sometime get black “cobalt spotting”). These reactive compounds greatly speed up the cross-linking process while reducing the temperatures needed to work the material.

However, application temperature is still a crucial factor as having too low a temperature will leave a significant amount of the unreacted starting material in the mix. The starting polymers are much softer and susceptible to hydrolysis and oxidation than the final crosslinked material. Gelcoat restoration is always a tricky process and the hazy appearance you see happens to a lot of manufactured fiberglass pools. It’s definitely not an installation issue. Poor water chemistry management and low quality manufacturing is usually the culprit. However, as you have seen, manufacturers will never accept the blame but rather classify it as a maintenance issue which relieves them of any warranty responsibility. It’s similar to how plaster problems (spotting, mottling, etc) are blamed on “water chemistry” when it has been clearly shown with technical studies that it’s an applicator/product issue.
 
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RunPool

In The Industry
Nov 7, 2018
3
Russia Moscow
Gelcoat materials are tricky. In general terms, they are thermosetting polymer materials. Typically thermosetting polymers start with a linear chain polymer and a mixture of shorter chain polymers which, when heat is applied, begin to cross link and harden. Once fully cross-linked, they become very hard and chemical resistant. They can not typically be reworked by heating as they simply break down when heated to high temperature rather than melt.

The thermosetting process can be quite slow with just heat applied and so the starting mixture usually has reactive cross linking agents added to it (organic peroxide’s) and sometimes a metal catalyst (cobalt usually which is why gel coats can sometime get black “cobalt spotting”). These reactive compounds greatly speed up the cross-linking process while reducing the temperatures needed to work the material.

However, application temperature is still a crucial factor as having too low a temperature will leave a significant amount of the unreacted starting material in the mix. The starting polymers are much softer and susceptible to hydrolysis and oxidation than the final crosslinked material. Gelcoat restoration is always a tricky process and the hazy appearance you see happens to a lot of manufactured fiberglass pools. It’s definitely not an installation issue. Poor water chemistry management and low quality manufacturing is usually the culprit. However, as you have seen, manufacturers will never accept the blame but rather classify it as a maintenance issue which relieves them of any warranty responsibility. It’s similar to how plaster problems (spotting, mottling, etc) are blamed on “water chemistry” when it has been clearly shown with technical studies that it’s an applicator/product issue.
Yes, you are right. It is a great problem to repair the gelcoat. Especially if it includes chips- little parts of coloured plastic or metal. Much better when gelcoat is monochrome- blue, white etc. To my regret there is no way to impregnate partially reacted gelcoat by something will make it less susceptible to hydrolysis and stop degradacion. but I will look for more)
 

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