SLAMing for a week now


Jun 11, 2019
Fairview, TX
I started SLAMing my pool about a week ago now when I noticed what seemed to be black algae. How I got that is somewhat of a wonder in itself. Although I hadn’t added chlorine to the pool in a couple days, because I had brought the level up to 7 ppm the last time I did add chlorine, when I noticed the black algae, the pool was still at 3 ppm (Pool Math recommends between 3 and 7 for my pool). In any case, I believe I’ve gotten rid of the black algae, and I don’t notice any other algae in the pool, but I haven’t been able to quit the SLAM process because I keep testing over 0.5 for CC.

The first day after getting rid of the black algae (a few days ago now), I did an OCLT and had less than 1 ppm lost chlorine and 0.5 CC or less. Later that evening I tested again and had 1 CC. So I just kept SLAMing.

Yesterday afternoon I tested after church (didn’t have time to test in the morning). FC was at 8 and 0 CC. I added enough chlorine to bring it back up to SLAM level (16 ppm), but I had a family emergency last night and didn’t have a chance to test and add more chlorine before bed. This morning I woke up and tested and FC was at 12 and CC at 1 again. What the heck is going on? Any ideas or advice would be appreciated.


Bronze Supporter
Jul 17, 2019
Prosper, TX (DFW)
I'm a newbie, but what I read is that you brought FC up to 16 yesterday mid-day, then this morning you tested and it was 12. A loss of 4ppm in an 18 hour period doesnt seem unreasonable to me, assuming your pool was in the scorching sun yesterday and today. I would still keep it at SLAM levels today, then do a real OCLT tonight and in the morning with no sun.