Citric Acid Chlorine Use


Well-known member
Jun 29, 2009
Vero Beach, FL
I had some iron particles on the bottom of the pool which stained the plaster. Most of the iron was vacuumed up and washed out of the cartridge. I had my water tested for iron and it did not register on the Taylor test.

I added 2 lbs of citric acid (SeaKlear), followed the directions, and it cleared the stains. However, it did not say my chlorine would be depleted. I learned that here. I tested for FC last night and was shocked that it was at 1.5 where it was 10 the night before. I added 2.5 gallons of 12.5% bleach and ran the filter for several hours. FC=15.5.

Question: How much chlorine will the ciritc acid use up?

I want to perform and overnight FC test because I'm worried about having the pool at FC=1.5 for 24 hrs. But don't want to do it until I'm sure the cirtic acid is all used up or else I'll be going crazy.


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
Citric acid and chlorine destroy each other fairly efficiently. If you are able to maintain an FC level above zero, chances are the citric acid is all used up.
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