How bad can it get? Can't confirm SLAM


Jun 21, 2019
Louisville KY
Hi, first closing. I need to close today. I have been maintaining SLAM level for 24 hours. Prior to the SLAM I brushed the pool and vacuumed up a few (less than 5) small leaves and bit of dust-like sediment from the bottom. I'm going to vacuum again as a bit of the 'dust' settled again. My pool water has been clear all summer. Water temperature is at 56 F and has been under 60 F for a least a week in my estimation, maybe even 2 weeks. CC is always 0 or under 0.5.

I've passed the clear water criteria, and CC is under 0.5 right now. I just won't be able to do an OCLT, and I'm worried about what if the bit of sediment accumulated in the slightly uneven areas of the pool (where the liner is depressed a bit into the sand floor) could cause a problem at opening (even if I remove it now visibly). If it IS algae after all, what is the worst that can happen - I open to a green or brown pool? Ugh. I am trying to avoid this but I'm afraid I will be worried now all winter long.

Last night at 11 PM I took FC up to 18, predicting it would be at 12 this morning. It was at 14 this morning. I'm at a CYA of between 20 and 30 right now.

I know there is no crystal ball, but.......thoughts? TIA.



Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
At your CYA level your SLAM FC target is 10-12. Trying to do a Overnight Chlorine Loss Test at almost twice that can be inconclusive.

I would just close your pool and deal with whatever in the Spring. Open your pool early while the water is still cold and it should be like you left it.