I have been lurking for a while now, and I have been on BBB for a couple of months now. This site is an awesome resource, and the people are great! Thanks so much!
After getting a lot of rain the past few weeks, I became concerned after seeing what appeared to be the beginnings of algae growth, in spite of never allowing FC to drop below 5. It looked like grey dust on the bottom that would disappear when brushing. It also felt neither slimy or gritty, so I decided to go ahead and SLAM and have done so for the last four days. After the first day of SLAMing, no more sign of "algae", and I have continued to maintain shock level until last night. Filter has been running 24 hours/day. The pool has been looking crystal clear through the entire SLAM process and continues to look great.
My test results this morning:
CYA 50-60 (I'm assuming 60)
Also, I lowered PH to 7.2 before starting the SLAM process
Now for my real question. Last night my FC was 14 (CC 0), and I did not add any chlorine to the pool, yet it read 16 this morning. Any ideas why FC would read 2 ppm higher? I have tried to be careful with my testing, always taking the sample about a foot deep in front of the skimmer. I am also trying to be careful with the drops to make sure I don't go too fast or too slow (no more than about 1 or 2 per second). One other important fact is that I installed a HASA Liquidator a couple of weeks ago, but I have had it shut off during this entire SLAM process (the flow indicator is at zero and I see no water movement in the 3/8" tubes).