Help: Staining in fiberglass pool

PooolGuyy

New member
Mar 18, 2019
3
Southeast US
Hi guys, I'm new on here and have something I need help with. I had a medium sized salt fiberglass pool installed late last summer so Im new to pool care in general. The white fiberglass has developed a tanish brownish greenish color that doesn't brush off. Its not just in one place, its all over (wherever the water is). Ive kept the pool running all year and didn't close it off since it usually doesn't get too cold where I live. Chlorine, ph etc is all high except alkalinity is too low. I've kept it relatively clean during the winter. Sometimes got a little dirty but nothing too much.

Does anyone know what staining is from and how to get rid of it? I've attached a picture. You can see its not the pure white that its supposed to be.

Thanks!
 

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mknauss

Mod Squad
TFP Expert
May 3, 2014
17,895
Laughlin, NV
Welcome to the forum!
Can't say I see much in the picture. Have you added any copper based algaecides, products with the word Blue in them, does your water have iron in it?

Can you be a bit more specific in your location? Can make a difference if you are in Key West versus the Blue Ridge Mountains.
Also please fill out a signature. Be sure to include what test kit you use to monitor your pool water chemistry.

I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
 

sktn77a

Gold Supporter
May 16, 2010
1,055
Chapel Hill, NC
Chlorine, ph etc is all high except alkalinity is too low.
High pH predisposes to staining. Get it down to 7.4 with muriatic acid. Then, an ascorbic acid tablet on the gelcoat surface will remove (dissolve) metal stains, a chlorine tablet will remove organic stains.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Hey guys, thanks for the replies. I've attached the test results that I had done today. Anyone know what the staining could be from?
Hey PG, I don't want you to feel "shut down" without test results from a TF-100 or Taylor K-2006C test kit. Just understand this forum recognizes either of those kits as the most reliable for home testing. Having said that ....... "IF" I was to take your Spintouch readings as accurate, I would immediately have concerns about the following:
- pH is too high; this increases the potential for metals to precipitate out and stain
- You seem to have iron in your water which is directly related to the note above (pH). If that's true, you should attempt to find out how you got iron. If you're on a well, that's probably it. The only way to remove iron is by exchanging it with non-iron water - usually trucked in. You can also use a good sequestrant to "contain" the iron.
- Your chlorine appears to be slightly elevated. Not in a dangerous sense for swimming, but for normal daily use with iron in water it can again add the potential for iron to stain.

As Marty said, we still encourage you to get a TF-100 or Taylor K-2006C. Make sure to use only regular bleach as your chlorine unless you have a SWG. Lower the pH right away to the mid-7s, and make sure to update yoru signature with all of your pool and equipment info.
 

PooolGuyy

New member
Mar 18, 2019
3
Southeast US
Hey PG, I don't want you to feel "shut down" without test results from a TF-100 or Taylor K-2006C test kit. Just understand this forum recognizes either of those kits as the most reliable for home testing. Having said that ....... "IF" I was to take your Spintouch readings as accurate, I would immediately have concerns about the following:
- pH is too high; this increases the potential for metals to precipitate out and stain
- You seem to have iron in your water which is directly related to the note above (pH). If that's true, you should attempt to find out how you got iron. If you're on a well, that's probably it. The only way to remove iron is by exchanging it with non-iron water - usually trucked in. You can also use a good sequestrant to "contain" the iron.
- Your chlorine appears to be slightly elevated. Not in a dangerous sense for swimming, but for normal daily use with iron in water it can again add the potential for iron to stain.

As Marty said, we still encourage you to get a TF-100 or Taylor K-2006C. Make sure to use only regular bleach as your chlorine unless you have a SWG. Lower the pH right away to the mid-7s, and make sure to update yoru signature with all of your pool and equipment info.

Thanks for the reply! I just bought the 2600c test kit from Amazon so it's going to take a couple days to arrive.

As for the iron, I don't know how that would be in my water since I'm on city water. Sometimes though, after it rains I will have little pieces of rock from the shingles on the roof that fall into the pool. Don't know if that has anything to do with with anything, but other than that, I keep my saltwater fiberglass pool clean. I'll be getting the water chemistry right when the test kit arrives.

Is there any product that I can buy at a local store that I can just test a small spot to see if it's an iron stain?

Thanks!
 

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