Fiberglass Hazing and Scale

[Bluffton SC Rob]

Moved from here.

Hello my name is Rob and I live in Bluffton, South Carolina. I just found this blog and am hoping I can get recommendations on the issue I am having with my pool. I own a 10k gallon fiberglass pool and hot tub. It is only five years old. My pool and hot tub, especially the hot tub, is suffering from severe calcium buildup on the sides and particularly on the flat surfaces. I do not know exactly what type of calcium buildup it is, but I am assuming it is silicate given how difficult it is to remove. I have been reading with interest Pat's (Texas Splash) posts about his pool issue over the years. From the pictures he has posted, my problem seems to be the same. I have attached some pictures below of what I am dealing with in the hot tub.

The first two pics show my hot tub after sanding the first two steps. You can see the difference between what was sanded and the lower step and main seating area that are still thickly coated with the calcium buildup. Adding to the frustration in trying to remove the buildup is that all the flat surfaces are textured. Even with the smooth walls it is impossible to get all the buildup off. After sanding, I then used two different brand names of rubbing compound (Meguiars Heavy Duty Oxidation Remover N49, and 3M Perfect-It EX 306060), but the hazing was still visible on the smooth surfaces, and it did nothing for the buildup in the pitts of the textured surfaces. I also tried to use CLR, Sodium Bisulfate, and Muriatic acid, hoping that one of these might just dissolve the buildup. But nothing seems to work, the way I would like it to work, or I am just not doing it right. When I used the muriatic acid, I would apply a few drops of the full strength acid to a small area then scrub with a stiff brush trying to get into the pitts on the textured surface. When scrubbing with the acid I did get up some type of flaking, but I do not know if the flaking is the buildup or possibly some of the gelcoat that came off. I have included a pic of the flakings that came off.



I would appreciate any help or advice that anyone can give me.

Thanks

 

[Texas Splash]

Welcome to TFP! Well, all I can say is I sympathize with you on this one. By all accounts from my own experience and the current science provided, we can only assume it's an unfortunate, unpreventable change of the gelcoat that could not be foreseen even if the water chemistry was maintained perfect the whole time. Before I forget, please post a full set of water test results with your TF-100 or Taylor K-2006C. The manufactures are virtually no help and will blame the issue on the owner anyways. I doubt the flakes coming off are any sort of calcium, otherwise it would've fizzled when acid was applied. That was the first test I was asked to do by Viking - lower water level to expose the top step and pour acid on it. No fizzle - not calcium. Viking referred to it as a form of oxidation, but would not accept any responsibility unless we had consistent (ridiculous/inaccurate) pool store testing.

My advice to you at this point is one of two things: 1 - You can continue to carefully sand/polish the areas of your pool/spa that you can reach, accept the results, and try to enjoy your investment; 2- Have a professional team come in and re-do the gelcoat. Because you appear to be quite vigilant in your efforts, you can also do like me when you're done with your buffing which is maintain exceptionally accurate logs about your water testing (TF-100 or Taylor K-2006C) and any specifics actions taken throughout the year to see if there is some sort of explanation other than a natural chemical reaction between the gelcoat and chemically-treated, well-balanced water. While our situations have some similarities, they also have some variances because first you have a spa and I do not. I have an SWG now (very recent), for for most of my time it was liquid chlorine. Not sure about your set-up (please update your signature by the way). We know the water changes are much more volatile in a spa versus a pool which is yet another factor we must consider when evaluating the "how's & why's" of what we have experienced. By the way, is the psa worse than the pool? If there is a common denominator responsible for what we are experiencing, perhaps we can prevent it from getting worse or recurring again in the future.

Hang in there. I know it's frustrating and exhausting. Please post some water test results, update your sig, and keep us informed of your progress and future status of the gelcoat - both what was originally effected and what you have re-done. Thanks for posting and great to have you with us at TFP.

 

[Bluffton SC Rob]

Thanks for the welcome and the advice. Frustrating and exhausting is to say the least. I am a novice pool owner this being the first. I purchased fiberglass, based on the recommendation of a friend who said it was far easier than a concrete pool to maintain. So I never expected to have to deal with this stuff. I have put a call into Latham the pool manufacturer but so far no call back. Actually my pool brand name is Trilogy, but from what I know Viking bought Trilogy, then evidently Latham bought Viking and a bunch of other brand names. I do not have a pool test kit, I have been using test strips, which until recently I thought was fine since I periodically (2-3 times a year) would take a water sample to my pool installer and let them test it. I have never had any clarity, algae, etc. type issues with my pool. My pool is completely screened in so I get very little organic debris in the pool. Since I live in Bluffton, SC, my pool is also open all year. So the best I can do number-wise is give you the results from when I last took my sample to my pool installer, and my best guess from what my test strips were showing as of today.

Pool Installer (as of March 13, 2020):
TDS - 1100, which they said is ok.
Saturation Index - Low
pH - 7.4, ok
TA - 87, low
CH - 68, low
Optimizer - 4, low
FC - .1, low
TC - .3, low
CYA - 150, which they said is ok?
Phosphate - 3381, super high evidently, I never remember even seeing this indicator before on previous tests
My test strip estimation from today:
Total Hardness (CH?) about 300
TC - 0
FC - definitely less than 1
pH - about 7.2
TA - 120 ( I added in alkalinity after I got the pool store results in March)
CYA - still looks like about 150
To my knowledge my CYA has been high for a long time, but my pool store has never said 'boo' about it. I recently had two other fiberglass pool people (from different stores) come out to look at my problem. Both of them were amazed at how high my CYA was, and they both thought this might have something to do with my issue. Both had no specific recommendation on anything easy to do about it, other than sand it, then use rubbing compound, polish, and wax. One even suggested I contact someone that gets oxidation off of fiberglass boats, so I did, and he came out and looked at it. He suggested sanding, rubbing compound etc., but he did not want to touch it himself because of the textured surfaces and too many curved surfaces, he said he would not be able to guarantee the results. So whatever was to be done was left to me.

I will be ordering a test kit tonight. I will update my signature/profile as soon as I figure out how to do so.

Thanks, Rob