I have had to SLAM my pool three times already this summer and now have to perform a 4th. I have had to add CYA three times this summer as well. The history of the SLAMS are:
#1 My SWG flow sensor had to be replaced (understand the need for this one)
#2 FC never dropped below minimum, but there was algae in the lights and under the ladder
#3 FC never dropped below minimum and no visible algae but cloudy water
#4 will be started this afternoon. FC never dropped below minimum. Had 6 people over yesterday and checked FC immediately after they got out at 5:00 PM and FC was 4.5 with a CYA of 80 so above my minimum. My SWG and pump turn off at 8:00 PM and my FC was 4.5 this morning when I checked at 8:00 AM just before my pump and SWG turn on. There is a thin film of green on the wall by the deep end ladder. There have been palm fruit berries in the pool, but we try to keep those up with a leaf rake.
Full set of test results:
PH 7.6 (just added MA to reduce to 7.2 to start the SLAM this afternoon)
It is a mystery why I am having to SLAM so many times when I'm not dropping below the minimum FC level. I target between 6-8 and my SWG runs at 40%. I should also add that for the very first time on Saturday, I added Cellulose Fiber to my filter, but hope that didn't cause this. The irony is that I finally felt I had dialed in my chemistry after the three previous SLAMS and wanted that extra filtering so the water would look clearer at night with the lights on. Any insight is greatly appreciated.