Stain Removal Advice Needed

[Karendrum]

This is my second year as a pool owner and I am struggling with major tan/brown stains. The stains last summer weren't too bad, only on the floor of the pool and steps. This year they are ALL over. All over the sides of the deep end, steps, pool floor. They look horrible and I am losing patience.

I just got done using a round of Periodic Products, No-Drain Stain Removal kits and the stains are the same. Today I tried Jack's magic stain identifier kit and none of the solutions seem to do anything to the stains. Used a chlorine tab on one of the stains and nothing is working!

The stains are light brown/tan in color. Besides draining the pool and acid-washing, is there anything else I can try?

Current water chemistry:
pH 7.2
TA 110
FC 1 (had to drop it and slowly increase after No-Drain stain eliminator)
CYA 60
Calcium Hardness 450

Here are a few pics, hard to see, but hopefully helpful.

 

[DeanP66]

Those look like classic iron stains. Have you tried putting some vitamin c tablets in a sock and rubbing them on the stain for a few minutes. If the stain clears or lightens, that would confirm that it's iron. You could try an ascorbic acid treatment for the entire pool if that's the case. It consists of:

1) lowering pH down to 7.2
2) letting FC drop near 0 (can be a bit risky when the weather warms up)
3) adding ascorbic acid all the way around the pool (generally 3 - 5 Lbs depending on the size of pool and the severity of the stains)
4) After letting ascorbic acid work for a couple of hours, add metal sequesterant (3 to 4 bottles) for your size pool. I use the ProTeam
Metal Magic brand and it works great.
5) Start bringing FC back up slowly. It will take a lot of dosing until FC starts holding. I would dose to around 6 PPM, and then check it
every couple of hours. It will be all gone, so you keep doing it. It's almost like a mini-SLAM except you don't dose all the way up to
shock level. Eventually, the FC will start to hold and you can slow down the amount of doses.
6)Add a monthly maintenance dose of Metal Magic (probably around 1 bottle for your pool). Sequesterant will get used up eventually, so you have to keep replacing it or the stains will come out of solution and will go right back on your plaster.

Your other option is to do the stain treatment, and once you're happy with the results, drain your water to get the metals out of the pool. Then just refill with fresh water and the metals are gone. Then you don't have to use the sequesterant monthly, unless your fill water has some iron in it. If you've got high CYA, this is the perfect opportunity to kill two birds with one stone when you drain the water.

Here is how my treatment went last August:

Before treatment:






After treatment:

 

[Karendrum]

Thank you Dean, I will give it a try. I just ordered Metal Magic last night. Glad to know I was going the right direction.

 

[DeanP66]

I hope you got if from Amazon. There's a guy there that sells it 4 bottles for $62. Best deal I could find.

This is where I got the Ascorbic Acid. It is very expensive, so you save if you buy it in bigger quantities.

5 lb Bulk Ascorbic Acid Powder | NewStore : PC NetwoRx Inc.