Brown stain and chalky substance on pool sides and bottom.. HELP!!!

[mahansc]

A little background. Fiberglass 12000 gallons, with ichlor30. Issue is brown stain on the sides and bottom of pool it just showed up one day along with the sides of the pool have a chalky substance on the side.
We’ve had our pool about 8 yrs now and have had almost NO major issues with our pool it’s like a info commercial set it and forget it just simply enjoy it. This yr not so much. I’ve spent more $$ trying to get rid of the brown stain and chalky sides then I’ve spent in the last two yrs on chemicals for our pool. I’ve tried metal free to get rid of any metal in the water, we’ve tried other stain removers with no luck. I can take a mr clean magic eraser and get 65-70% of it off. The chalky stuff I can take my hand and rub it off and it makes the water cloudy. Now I’ve taken some old towels attached to our pool brush and scrubbed the entire inside of the pool, that seem to remove some but it’s back a few days later. I’m ready to empty the pool acid wash and start over. On a side note I’m enjoying the lake more so than our pool which is really bad. We had a new ichlor 30 installed about 4 weeks ago . since our last aqua rite went south on us and we have been fighting the demand for chlorine since they installed it. Out pool is12000 gallons. The last water sample numbers were ph 8.1; free chlorine 10.9 ( I added 6 gal of liquid chlorine sine the ichlor30 wasn’t producing enough), alk 89; total chlorine 10.9; hardness 207; cy 109; tds 5000; minerals 3782, .. so can anyone help me figure this out. I love to come home grab a beer and go float, cut the grass and then go jump in to cool off. Any help is appreciated. I’m sure I left out tones of info pls just ask and I’ll provide the info if I know it.

 

[Texas Splash]

As a FB owner myself, and having posted a recent (long) thread about FB care and issues, I have a sneaky suspicion your issue lies with questionable testing and keeping the pH in control. The result - calcium scale trying to precipitate to the shell. This is just my initial assessment of course, but it's very possible. A few things you could do to help this thread for more answers:
- Update your profile location (city/State). It makes a big difference
- You really need to test your own water with a TF-100 or Taylor K-2006C. We don't care where you get it, or which one you get, but those two are easy to use and reliable, not to mention on-hand when you need it. Store testing will bite you in the rear.
- If your CYA is close to that number, it's too high. Your SWG can't keep up.
- Speaking of SWG, it's creating aeration which also increases your pH - something that's already too high

Right now, it's really important for you to get that pH down to about 7.4-7.5. It's also critical you obtain one of those recommended test kits and post a full set of your own numbers. You'd be surprised the difference it makes. If that substance is faintly removeable, I'd do it now before it adheres even more. Once it sets-in, it's a bear to remove. Ask me how I know.

 

[mahansc]

As a FB owner myself, and having posted a recent (long) thread about FB care and issues, I have a sneaky suspicion your issue lies with questionable testing and keeping the pH in control. The result - calcium scale trying to precipitate to the shell. This is just my initial assessment of course, but it's very possible. A few things you could do to help this thread for more answers:
- Update your profile location (city/State). It makes a big difference
- You really need to test your own water with a TF-100 or Taylor K-2006C. We don't care where you get it, or which one you get, but those two are easy to use and reliable, not to mention on-hand when you need it. Store testing will bite you in the rear.
- If your CYA is close to that number, it's too high. Your SWG can't keep up.
- Speaking of SWG, it's creating aeration which also increases your pH - something that's already too high

Right now, it's really important for you to get that pH down to about 7.4-7.5. It's also critical you obtain one of those recommended test kits and post a full set of your own numbers. You'd be surprised the difference it makes. If that substance is faintly removeable, I'd do it now before it adheres even more. Once it sets-in, it's a bear to remove. Ask me how I know.

Texas splash,

Ok I'll bite "HOW" ., what did you use or how did you get rid of it? I should have added I did get the PH down to 7.6 and it's been sitting there for about a week now. I'll add that data to my signature. and I have come to the realization that the pool store I go to and have since we had the pool installed are clueless at least the new peeps that are in there are. I'll look on the site for those test kits and order one asap.

 

[Texas Splash]

what did you use or how did you get rid of it?

In my case, I went from early elevated CH (scale) to what I believe to be the exact opposite - oxidation. I don't see that as your issue. But the elevated pH could certainly give the CH in the water reason to look for a home on the shell. It can look dull and dingy. Just to rule-out other items you could do the following:
- Rub a chlorine tablet on the area for a few minutes (organic)
- Rub crushed vitamin C tabs in a thin sock or nylon for a few minutes (iron)
- If the vitamin C reacts the opposite of lightening and makes the stained area darker, it could be copper, in which case you could try with dry acid in a sock.

But based on some of the things you described, I'm leaning towards calcium. But getting one of those test kits is definitely a step in the right direction.

 

[mahansc]

Update I’m ordering the test kit as suggested. Now I put a bottle of scale inhibitor in the pool and following directions per the bottle. As a side test I sprinkled small amount around the steps and the brown stain come right off in less than a min. So would it be safe to say the brown stain is iron? If so should I just let the inhibitor run it’s cousre then tray the stain? If I use the vitamin c stuff what pool chemical does it lower or raise?

 

[Texas Splash]

Vitamin C is just a simple ascorbic acid. You can use whatever product you wish now that you know it's iron. Just watch for other ingredients or possible side effects. Ascorbic acid and vitamin C shouldn't change anything, but may require a slightly low FC level during treatment. There are many other products on the shelf, so you'd have to check those instructions for any specifics. Also watch FC closely as some scale products are known to eat-up your chlorine level.