Ascorbic Acid Treatment for Copper Staining


Bronze Supporter
Jul 27, 2016
North Potomac, MD
I started Ascorbic Acid treatment for copper staining yesterday. There hasn't been much change after adding 6 lbs of AA for a 24000 gallon pool. That's more than twice what is recommended, but the pretty sparkly blue staining is pretty much all over the pool. This has developed slowly over time, but seemed to get much worse last year after I performed a very high concentration SLAM because of a CYA that was over 150. Before I started my test readings were
PH 7.1
FC 0,2 (just the tiniest haze of pink that one drop eliminated)
CC 0.0
TA 80
CH 310
CYA 50
Temp 60
Adding the first 1.25 lb of AA caused some browning, that disappeared. After an hour I added another 1.25 lb. Saw a bit more browning, that dissipated. In the evening I added another 1.5 lb, thinking that I had more than I thought and would need more acid. I left it to work overnight. Not much change this morning. Some iron brown dots among the blue are definitely less obvious, but the blue is not showing much difference. I added 2 lbs more AA, so now have added 6 lbs. I think the blue is starting to fade a bit, but it is hard to tell. I have not added sequestrant yet.

I am wondering what my next step should be. I am concerned about adding more acid. I don't have a heater, but I don't want to eat away at my plaster. I have read all the posts I can find on copper treatment, and see that sometimes the thought is that you just have to live with the copper.

Should I
a) keep adding AA until I start to see an effect
b) let it go at this concentration and see if it is just taking time
c) add sequestrant and see it that helps over time, if necessary planning another treatment after a few weeks?
d) give up and enjoy the pools "character"
e) none of the above...your advice more than welcome!


TFP Expert
Platinum Supporter
May 23, 2015
Tucson, AZ
AA doesn't remove copper stains very well especially if they are old stains.

You need to use a different treatment method. Jacks Magic has a copper stain removal based on sulfamic acid which works very well.

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