I have really been struggling with my SWG this year. I have never had problems before, but this year I have not been able to keep my chlorine levels stable. I SLAMmed the pool about a month ago and went up to the mustard algae shock levels just in case there was any of that around. I scrubbed out my light niches, backwashed, etc. The pool passed the OCLT and had no measureable CC. Once that was achieved I started raising my CYA from 30 up to 65. After a few days when the FC dropped down to the 12 ppm range I started working on setting the run-time for the SWG. I found that running it at 100% for 12 hours a day was not enough to maintain the chlorine levels. It is now about a month later and I am still having to run the SWG at 100% for about 18 hours a day to maintain FC in the 7-8 ppm range. I noticed my PH is drifting up fairly quickly. After reading on this forum, that is probably because I am running the SWG for so long. TA was 120 several days ago. I have been adding muriatic acid to knock the TA and PH down and will continue to do so, but would high PH and TA cause increased chlorine demand?
Yesterday had a surprise. The FC dropped from 7 down to 4 and CC went from 0 up to 1.5ppm (the pool was only lightly used and it was a mostly cloudy day). What could cause that? I had not seen any measurable CC since completing the SLAM. Could the muriatic acid cause that?
This is probably a good point to show my numbers from yesterday after adding a gallon of muriatic acid:
CH: 100 (need to work on bringing this up)
Should I try another OCLT to see if there is something in the water using up all the chlorine? It looks like the generator is working- I see lots of cloudy water coming off the cell. Also, the solar panels are new to my system. Could the extra 4 or 5 degrees they are adding to the water over previous years increase the chlorine demand by that much? In the past I have only had to run the generator for 11-12 hours to maintain chlorine levels. Is trying to maintain the level at 7ppm harder than trying to maintain it at 4?
Thanks for any help or ideas.