I've been around here for a while and had the most successful pool season in 2012 thanks to you guys and gals.
I got my 14' x 48" AGP setup 2 weeks ago. I've been adding packets of dichlor I had left over from last year in order to both chlorinate and add CYA. I have been trying to keep it at near or above shock levels in order to get CYA up to spec.
Unfortunately, in spite of regular testing, apparently FC got as low as 2. Apparently that caused a problem.
I have the TF-100 kit w/speed stir.
My results this morning were:
FC = 4
CC = 1
PH = 7.5
TA = 120
CH = 120
CYA = filled the tube all the way up (20 is the last mark) and the dot was approx. 50% obscured... so I'm guessing 10ppm, although the fact that I added 32 oz of dichlor should have raised CYA to 30 for a 3900 gallon pool. Not sure what happened.
I added the appropriate amount of bleach to get me to 12ppm at lunch time. I retested after an hour and it was on target.
I tested again at 9pm ( 8 hours later) and FC was 11 and CC was barely .5.
Is it normal to have CC drop that quickly with only a minimal drop of FC? I always figured that in order to burn CC I'd have to use up much more FC than I did.