Dear Pool Geeks,
Ph 7.5 (just added acid to get to 7.2)
Here's my issue:
The water is clear and beautiful, yet the FC is 0. My oversize RJ45 CircuPool SWG is running 24/7 at 100%. I can see gas clouds through the ionizer, so I know it is working. I added a lot of shock early in the season that wouldn't stick , but found my CYA was a very low 10. I have added dry acid this year to raise the CYA to an almost-too-high 80. Now, after raising the CYA, I'm still adding shock, but with no rise in FC. I think I have a subtle algae bloom, but it could be chlorine lock, or a combination. After reading countless forums, I think the answer is to get to Breakpoint Chlorination, but I feel that the information out there is a little inconsistent.
Using the Chlorine/CYA chart from this forum, I see that a shock value of 31 is recommended. Yet this is higher than the pool calculator's suggested shock level, which recommends a 21. Also, when I read about Breakpoint Chlorination, it seems to be a one time process, yet the SLAM program looks more like an ongoing process over several days.
So, is SLAMming the pool is different than the Breakpoint process? Since I have no visible algae, should I use different shock levels? I just want to do this right, hopefully for the last time this season. If it takes a few days, I need to be sure I have enough chemical on hand so that it doesn't get away from me if I run out.
Thanks for the help, and please don't flame me for asking a question that may have already been answered. There are a lot of threads to sift through, and I feel like the clock on the algae bomb is ticking...