I can't figure out what's going on with my pool. I switched to the BBB method 2 summers ago and generally, it has worked for me. But I find I'm spending a lot on bleach because my pool water drops to around 0 FC after a bleach slam the day before. And of course, because it won't hold an FC level, I start to get algae.
The readings on my 20,000 gal plaster pool are as follows:
PH = 7.4
TA = 110
CH = 500
CYA = 50-55
Borates = 60
I run the pump 6-8 hours/day.
I have enough CYA that my pool should be holding a steady FC level. But after shocking it (putting in enough bleach to bring it up to ~16ppm FC), it is down to 0 again in less than a day. What gives?
I have already followed the directions in the article about turning your green swamp into a sparkling oasis, and the overnight test showed I had eliminated all of the algae. But now it's creeping back again because the pool won't hold the bleach. Should it be growing back that fast (less than a week)?