Hello Jason,
I went with ascorbic acid a 5# bulk pkg for $57.50 + $7.5 shipping for a total of $65.00. I found that Natural Chemistry's 'Stain Free' (1.75lb/$30.00 x 3 units of Citric Acid) would have cost $90.00 (even with free shipping), and if, as you say, I would need twice as much citric as opposed to ascorbic, then I'm confused. Isn't the Natural Chemistry's product Citric Acid? If Not, where do I buy bulk Citric Acid, in the event the already ordered 5# bag of ascorbic acid is not enough to remove the staining? In the last week, I have spent, literally, hours scouring this and other pool care sites to the point that I'm now pretty confused about a lot of pool care issues. I have had my pool for 17 years and never, until this year, had any issues with staining or chemical imbalance. I opened the last week of May and could not stabilize my chlorine (46,000 gal/ used over 30 gallons of liquid chlorine and NEVER got it to hold). I have been reading all of the conflicting views/positions regarding 'breakpoint'; whether to use liquid chlorine/bleach or calcium hypochlorite; or whether or not to ever shock. Then I tried to educate myself about the cyn/chlorine ratios. My cyn is low so I added 8lbs of stabilizer, cyn never budged from 'low', (this was a week ago). Shortly after the 2nd week of opening and trying to no avail to balance the chemicals, the stains appeared. So my current plan is to leave the PH at 7.2; the CYN at 0; and the chlorine at 0. I just added 160z of polyquat 60 to control algae until I get these stains out, then I will again try to balance my pool. Any suggestions regarding following this course of action? Thank you for your input.