Draining your newly plastered pool will ruin it.
Whoa! Please elaborate. TFP expert mknauss suggested it was the way to go suggesting the SLAM would go really quickly.
Draining your newly plastered pool will ruin it.
I don't remember any tfp experts suggesting that you drain your pool. New plaster should never be exposed. Exposed to air sun and heat can cause it to crack and fail.
Black algae is handled differently -- Pool School - Black Algae
I have been wondering - with your small pool water volume, could you not drain this pool and then do a SLAM on the new water? It should go really quick. You can keep the FC at shock levels and keep the pool open. It would just be best to test / dose every couple hours. You would only have to keep the swimmers out of the pool for 15 minutes if adding chlorine.
Take care.
Good luck on the OCLT. Even with the 7+ bathers today, I hope for less than yesterday's 3-3.5 losses.
Your observation that you're losing too much in the daytime is fair. Increasing CYA to 80 either over a few days or overnight might be your best bet if you're going to continue the full SLAM after getting CYA standard to ensure proper testing.
If you want to hit the pause button on the SLAM, perhaps target FC 9+ and just burn the SWG as high as needed, accepting that you'll just replace the cell sooner than if you used a lower %, but spend less time on bleach. Another option, totally not TFP, would be to only add bleach after pool is out of direct sunlight, bleach up to slam each evening to chip away at it with minimal time. This certainly isn't usually the most economical path, but in your situation, given that you are busy, given that you're not 100% on the CYA, and given that you are keeping it above target and usually crystal clear, it could be considered as an option potentially. It isn't necessarily smart, and yet, it is what I as a pool owner might do temporarily... anyway the TFP guide in me suggests you get your CYA testing beyond doubt (cya standard) and raise CYA to 60-80 and SLAM until you pass all three criteria.
Since you eliminated the sand filter as being the leading issue, best to go back to adding bleach in front of returns, if you haven't already. Pour slow and enjoy the blinding sparkle of summer water.