Recently did a successful SLAM - the scrubbing the sides, tiles with toothbrush , and digging up bits of black algae from the floor , did the trick in about 4 days.
Always had perfectly clear water , and good balance, but was losing lots of FC.
Since then, over the last two weeks (except a 3 day period when my pump blew out and so I had to wait for a new one to be installed) , everything has been ticking over fine - all levels good. Even since new pump installed 1 week ago, I have been tweeking and got it stable at 6 hours run time, at 40% on the SWG, holding nicely at FC 7-8.
Last 2 days , I noticed it not holding, so increased to 50% , then 60% - it was then struggling to hold at FC 6 yesterday - even though it was a cloudy day.
Last night, I kept pump running and turned SWG up to 80% , this morning at 9.30 am it was at FC 8. SO basically with it running all night, it only gained 2 ppm.
What does this tell me? Something is eating the FC? Not badly right now, but could be something , right?
I have turned it to super CL for now, to see if it can fight it off without a SLAM.
Is it possible , if you catch it early, to increase the SWG and leave it running , to kill off what is eating the FC? OR, is it always going to be a losing battle and I will need to do another SLAM?
One last thing, the only thing I did not do on last SLAM , was remove the light fitting and clean. As it passed, does it matter, or should I do that as a priority right now ?