Lost my mind and messed up the Ascorbic acid treatment, how to recover?


Active member
Jul 20, 2014
St. Louis, Missouri
Okay, last year we put a canister of Ascorbic Acid (Stain Free or something?) and the stain was gone completely in 30 minutes. Did not use sequestrant so it returned eventually.

This year we were going to do it properly. Bought bulk ascorbic acid and Jack's Purple Stuff and other chemicals needed to maintain.

Brought chlorine down to 0 and PH to 7.2 and began Ascorbic Acid treatment one week ago!

Our inground fiberglass pool is about 8800 gal. and I used about 3/4 lb AA with filter in circulate. The stain was not completely gone after 1/2 hour so I repeated process, still not gone so I repeated twice more for like 3 lbs or better of AA. Ran for 24 hours and stain finally disappeared. Added a full bottle of Jack's.

Started trying to bring up chlorine with 6% Bleach and I still cannot hold chlorine. I turned the IC40 SWG gen all the way up and that still isn't holding.

I got desperate, fearing an algae breakout or something and threw a bag of shock in yesterday evening. Now my stain has returned and the chlorine is again back to zero with the swg set at 80%. Why is my chlorine still dissipating so quickly???

To top it off my Calcium hardness tested low for 3 days at 120 so I added 195oz of Calcium Chloride per the pool math calculator 2 days ago and today it is at 425 which means a whopping 30% water change.

I don't know what to do........Here are tonights numbers: HELP PLEASE and THANK YOU!!!!

Temp 84
FC 0.5 (next try was 0)
CC 0.5
PH 7.5
TA 90
CH 425
Salt 4050
CYA 60


TFP Expert
Feb 3, 2014
Central Minnesota
I wouldn't be overly concerned with the CH. It doesn't matter much in your fiberglass pool provided it's not EXTREMELY high to cause a "scum" line at the water line when water evaporates and leaves a calcium ring.

Sounds like you panicked a bit on too quickly raising your chlorine level and not maintaining the pH constantly as you can down at 7.2 or LESS throughout the process until you slowly bring up your FC.

It's normal to take quite a bit of chlorine to bring things back once you start balancing again because the residual ascorbic acid will react/consume your chlorine. You just have to make sure to do it slowly while maintaining low pH.


TFP Expert
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Moderator Emeritus
Aug 10, 2012
FL panhandle
Yes, as soon as the stains are lifted, or an hour or two after, start raising FC 2, 3 ppm every hour or more until you get to minimum and hold. Test and add bleach often because the AA will consume your FC quickly. Once you get to min and it holds then go a couple above it and aim for low minimum for you CYA, [FC/CYA][/FC/CYA] and keep it there. All the while keeping pH at 7.2.

Leave the SWG off because it is going to push up your pH and it doesn't make FC fast enough to help anyway.

If you have more AA then add it now and start over.


Active member
Jul 20, 2014
St. Louis, Missouri
Thanks for your responses. We went and bought 10 gallons of bleach today to start the AA treatment again.

Got home and did a quick check of chlorine and ph and OF COURSE chlorine is now sky high (only did the daily test which maxes at 5 and we are maxed for that test). I guess we finally reached the tipping point where the chlorine could keep up. Aghhhhh!

Anyway......... unplugged the SWG, am adding Muriatic Acid to get the PH down and will wait for the chlorine to go back to zero.

I am guessing I should once again add some Jack's purple after the stain treatment or is the initial dose enough?

If I am understanding this, I shocked the pool which caused the iron deposits to be released from suspension and back onto my pool surface?

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