No drain acid wash - muriatic or ascorbic

Drew80

Well-known member
Feb 26, 2013
139
Austin, TX
#1
I have a brand new pool that is stained because of an improper startup. I have all kinds of pretty colors that aren't the color of my plaster - brown, green, sort of a pale blue. I'm researching what I can do to get rid of them and bring back the plaster color.

I've read about removing metal stains by doing a no-drain acid wash - basically add muriatic to bring the pH down to about 6 and let it sit for a few days with lots of brushing. Muriatic will basically eat anything, but it's pretty harsh and I don't want to hurt my plaster.

I've also read that I can dump in a ton of ascorbic acid, which is less toxic, works well against iron, and will also remove stains fairly easily. I'm fine with trying it, but I don't want to waste my time/money.

I need some opinions on both. I like the idea of being less toxic, but I really just want to remove the stains. I'm also not sure what types of metals I actually have. Any help is greatly appreciated.
 

Drew80

Well-known member
Feb 26, 2013
139
Austin, TX
#4
I did an acid bath on the spa side to test it before doing the whole pool. My spa is 1,100 gallons, so I put in about 30 fl oz of muriatic to bring it down to a ph of 4.5. After about 2 days of that and lots of brushing, the plaster now has a white haze on it (it was a dark blue). I neutralized it to keep from doing any more damage (if that is damage). Any idea what's going on?