Brownish stain covering most of pool walls and floor

[blairsooley]

Hi all, this is my first post, though I've learned a heck of a lot from this site thus far. I've gotten to know my pool over the last 9 months and have the TF100 to keep chemicals in balance. After returning from 2 weeks away, the chlorine in my pool had reached 0 (my liquidator ran out of bleach). I have finished the SLAM process and now everything is in balance, however, I have a slight brownish discolouration on most of the walls and floor that I can't sweep off. This didn't all happen during this trip, rather it occurred over time but much worse lately. Last year I had the same thing and while replacing some of the water (because of high CYA), I used Muratic Acid to remove it. I tried to take a picture but the difference in the brownish areas and the blue areas are not visible in the picture.

Can someone tell me how to remove this stain and keep it away? Thanks!

 

[blairsooley]

Just found the section on Stains in Your Pool. I expect its iron and will try the Vit C test. I'm on municipal water so this seems strange.

 

[blairsooley]

Tested with crushed Vit C pills in a sock. Placed on spot with a rock and put a rock on top, which puffed out some of the Vit C dust. In 10 minutes the area covered by the sock was unchanged but the surrounding couple of inches was much less stained. Assuming stains are iron.

 

[Akathisia]

Sounds like you are on the right track. Just bumping this up in case somebody has other ideas for you.

 

[denniswiseman]

I have used the Ascorbic Acid Treatment with reasonable success
I have also used Purity Pool Underwater Acid Wash Kit, which uses muriatic acid. I did purchase a 1/4" plastic valve so that I could control the flow of acid
You will also need to add a sequestrant after use to hold the iron in suspension
You can by larger quantities of Ascorbic acid on Ebay

 

[blairsooley]

Thanks for the suggestions. I purchased bulk Ascorbic Acid on eBay and am now awaiting the delivery of algicide before dropping the chlorine. Any suggestions for a sequestrant and will this be something I need to regularly add until the water is eventually changed? I believe I identified the source of iron as a wire (coat hanger?) that had been used to secure something. I found it when rebuilding some pool light fixtures and it was nothing but a pile of really fine rust particles on an extremely thin wire. When I touched it, it fell apart in my hand and the rust went throughout the pool water. That was months ago and I never gave it another thought until now. As a final note, I have read that most plaster pools like mine will eventually get a brownish discolouration on the surface that requires an acid wash. Is this essentially what I'm doing with the Ascorbic Acid treatment?

 

[denniswiseman]

Thanks for the suggestions. I purchased bulk Ascorbic Acid on eBay and am now awaiting the delivery of algicide before dropping the chlorine. Any suggestions for a sequestrant and will this be something I need to regularly add until the water is eventually changed? I believe I identified the source of iron as a wire (coat hanger?) that had been used to secure something. I found it when rebuilding some pool light fixtures and it was nothing but a pile of really fine rust particles on an extremely thin wire. When I touched it, it fell apart in my hand and the rust went throughout the pool water. That was months ago and I never gave it another thought until now. As a final note, I have read that most plaster pools like mine will eventually get a brownish discolouration on the surface that requires an acid wash. Is this essentially what I'm doing with the Ascorbic Acid treatment?

Make sure your algecide is a polyquat
I not sure what is available in the states but I use Lo-Chlor No More Metal. It is suggested that you have top up doses to hold the iron in suspension
Ascorbic acid is what it says, acid, but quiet mild. The acid wash uses Muriatic acid and is a lot stronger but when using the under water acid wash be careful how much do do in one time as it will lower your pH and TA. When I did it I raised my pH and used enough acid to bring down to a pH of 7, aerate to bring it back up and repeat

 

[pabeader]

A number of us stain victims have been trying different products and have found that Pro Team Metal Magic works real good. No messing with FC, pH or algaecide. Find it for a good price on Amazon buy from Pool Geek. Be careful though, there is a poolgeek, too. Not the same seller.

 

[blairsooley]

To complete this thread, I did the ascorbic acid treatment and it seems to have done a reasonable job or removing the brown stains. Used Metal Magic to sequester and that seems to have cured the issue. Now on to the next problem.