organic stains on pool walls and floor

[carlbob]

I had to go to the pool store today to buy some calcium chloride. Was talking to the store owner about the ugly organic stains on my walls and floor. I have already done the slamming process for 2 weeks as recommended by one of the tfp experts, but it didn't help with the staining. He said they acid wash pools all the time just by adding 3 to 4 gallons of muratic acid to the pool water and then let it circulate through the pump and filters for a couple hours and then shutting the pump off and letting the pool water sit for a couple of days. Then neutralize with baking soda afterwards. Has anyone ever heard of doing such a thing? Would this process do any damage to my DE filters or to the pool pump or plumbing? Thought I would ask y'all as there is much valued knowledge here.
I don't want to drain the pool to do an acid wash since we have had a lot of rain and I don't want to float the pool.

 

[Coach_1]

I'm having the same problem. Can you post a pic? What color are the stains?

 

[censored]

Have you tested the stain yet using the Vitamin C & Trichlor Tab methods? If you want to test the effectiveness of an acid wash, you can stick a pvc pipe down on top of the stain and dump a little acid through the pipe. Just be careful though, I got a nice black streak on my old plaster from doing this.

 

[carlbob]

i know its organic stains because over the winter before I found this site I had been using chlorine tablets and granulated shock. The bottom came of the tablet floater and the tablets landed on the pool floor. There are nice bright circles where they had been sitting.

 

[censored]

Are there many spots or just concentrations? There is a brush attachment you can find out there that has a little reservoir to hold acid so you can do it yourself without draining. Obviously this would be a big feat if there are stains all over.

 

[pooldv]

That doesn't necessarily mean it is organic because trichlor is also acidic and if it sat there for a while the acidity could have removed the stain and not the chlorine. Put so Vit C on it an see if the stain goes away.

The acid bath process is called a no drain acid wash.

 

[carlbob]

Ok I took your advice and took a vitamin c tablet and rubbed it on a 4x4 area of the pool wall. Most of the staining has disappeared. I live in the city of arlington and I wouldnt think we have metals in the water, but maybe so. These stains have been in the pool since we bought the house 2 years ago and they just bug me. What can I use to get rid of them now that I know what they are and can I get whatever it is locally? One person said you can just dump in vitamin c tablets, but I really have no idea.

 

[censored]

You need to do an ascorbic acid treatment. You can find the process here on the forums. Basically you dump in 2 pounds per 10,000 gallons and then use a sequestering agent like Jack's magic stuff. You will need to drop your FC for a bit so you need a non metal, non shocking algaecide. Amazon is without a doubt the cheapest place to get ascorbic acid. Leslie's did have a buy one get one free on their site which makes it a doable deal. You have to find it on eht site and have them match it in store.

- - - Updated - - -

Here, found it for you: Leslie's BUY ONE GET ONE FREE Stain Remover, 2 lbs.

Amazon is still better on bulk ascorbic acid, but at least you can get this now if you have a Leslie's close.

 

[pooldv]

Your source of metal is likely not from the city water supply. Other sources for copper are mineral/copper systems, algaecide, corrosion from a heater if it has a copper heat exchanger and PH is low.

More here, Pool School - Metals in the Water and Metal Stains

And here, Ascorbic Treatment to rid Pool of metal stains

If you know /identify the source and confirm it is not your water supply you can do partial drains and refill to lower the metal content until it no longer stains. Otherwise, you will need to add sequestrants regularly.