Ph dropped after clearing pool with SLAM


Jun 12, 2018
Glens Falls NY
Didn't add enough chlorine to the pool before we left for the holiday weekend, and with the hot temps in the northeast, came home to a pool that was starting to go green. Started SLAM (Walmart bleach) Sunday evening with ph at 7.2

Water back to blue but cloudy on Tuesday, passed OCLT, brushed and vacuumed to waste and kept SLAM. By today pool was clear with small amount of dead algae that I vacuumed to waste. Chlorine was still high this morning but between topping off with fresh water and a 93° full sun day it dropped as expected.

Tested after dinner:
FC 5
TC 5
Ph 6.8 (I didn't bother checking during slam)
TA 60
CYA 40

Should i add borax first to bring the ph up or baking soda to raise TA??? I don't recall ever having ph drop that low after finishing SLAM


TFP Expert
Mar 2, 2011
If the pH drops while doing a SLAM with bleach, it usually points to ammonia. It's possible that bacteria got in the water and began to convert cyanuric acid to ammonia. You probably caught it mid process.
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