I did a vitamin C treatment last week to remove iron stains. Waited for chorine level to drop low. pH was 7.2. Added some polyquat. Everything was going fine until today when we received about 1 inch of rain. Now the stains have returned. I don't really think the rain has anything to do with it, but it's the first day that the chlorine level has held relatively stable for the last 24 hours. I only brought it up to about 2.5 which is the highest it's been since the treatment. My pool is 33,000 gallons and I added a quart of Metal Free after the stain treatment. I had already added 4 quarts of Metal Free prior to the treatment hoping that the Metal Free alone would take out of stain. I figured that would be an adequate amount of Metal Free since it's about twice the recommended amount.

OK, so now should I repeat the treatment and use more Metal Free? Or, did I raise the chlorine level too quickly? Or something else?

Current levels are:

TC 3
FC 2.5
CC .5
pH 7.4
TA 60
33000 gall Vinyl
Sand filter

Thanks,
BobbyC