Tan Stain In Plaster Pool

[maker]

I had my pool replastered last year and this year upon opening there is a tan colored stain covering about half of the deep end. I have the PH at 7.3 and have maintained shock level 30 for about 4 days and scrubbed the stain to no avail. Right now the TC is around 5. I have tried putting vitamin C in a sock and holding it against an area of the bottom for 30 minutes and don't see a white spot in the stain like it should if it were a metal stain. Any ideas?

[waste]

Welcome to the forum,maker! I've used this on smaller stains - don't know how well it'll work on your monster. I don't know what your chem values are, so the choices vary. If you have room in your water for cya, try putting 'pucks' (tri chlor) on the stain and wait until it (literally) 'bleaches out'. If your cya is high, but you can stand some extra calcium, put some cal-hypo in a stocking(ie womens knee highs or the bottom part of your wife's old pantyhose), with a rock to keep it in place, and let it sit there for a while and see if the stain is lessened. Can't think of a way to make these suggetions cover a larger area, however, if you scuba, you might try mixing up some muriatic acid in a pump sprayer(with some ballast in it) and applying it directly to the stain.
Of course the obvious answer (which just came to me) is to call whoever plastered your pool

Congrats on knowing enough to try the acorbic acid first!!!

[mbar]

You can try putting some ph down in a sock and rubbing it on the stain - if this doesn't take the stain off, and the vitamin C didn't work then it may not be a mineral stain. You may not have used enough ascorbic acid (vitamin C) on the stain for it to have penetrated the sock. It is only a guess from me. But if these don't work, then it is coming from something other than metals.

[maker]

Upon further inspection, I believe there may be a whitish spot where the sock was. It has to be a metal stain because I've brushed the heck out of it and had a shock level of 30 for 4 days.

I will look around the forum to find a method of removing it, but if anyone wants to repeat here then feel free.

[mbar]

You may have had the metal drop out with the high chlorine level. You can remove the stain by using ascorbic acid, which can be bought online at:

http://www.msm-msm.com/store/agora.c...scorbic%20Acid

or:
http://www.chemistrystore.com/Ascorbic_Acid.htm

When you use the ascorbic acid, you must also use a sequestering agent, such as Metal Free, or Jack's Magic, Sequasol, or any product that says it suspends metals in the water. The ascorbic acid will bring the metal that precipitated out of the water and landed on the surface of the pool back into suspension. Then the metal free will hold the metal in the water. You will have to bring the chlorine level down in your pool before you use ascorbic acid, because the chlorine will use up the ascorbic acid, and you will need more to do the job. There are products to take the chlorine out, or you can wait till it comes down on it's own. The ascorbic acid will bring down your ph, so you don't have to worry about that. If you decide to use the ascorbic acid, I will help you do the process. THere are also other products on the market that will do the same thing. I have found the ascorbic acid works well for me and is cheaper than the others. Feel free to ask any questions you may have.

[maker]

Ok, I ordered some absorbic acid, but I am still not sure if it will work. What is the best sequestering agent and I will order it as well. Here are some pictures. Anything look familiar? The little white circle is a return and the two larger ones are where some circular stones fell in over the winter. I cover my pool with a tarp and use the stones as weight. The wind pulled in some stones unfortunately.

I would definitely appreciate your help mbar. I don't want to drain!

[ksturge]

I have a vinyl liner pool with almost exactly the same problem. I did the chlorine raising thing, with no change. I've put Vitamin C tablets on the stains and after about 20 minutes, the stain starts to turn black and you can begin to scrub. It seems to be working. My question is : I want to fix this quickly. What is the fastest plan. I don't really want to wait for pounds of ascorbic acid to arrive. I do have to get something to bring down the chlorine. I'll add acid to bring down the ph. Then what : a metal product to remove the stains? Help !!!