AquaChek 7-in-1
Free Chlorine reading of 0.5 ppm
Low
What it means
Free chlorine at 0.5 ppm is on the edge. Pool will tip into bacterial growth within a day if not raised. Below the safe-to-swim threshold.
What to do
Add enough chlorine to bring the reading to 2 ppm. For Cal-Hypo, roughly 0.25 lb per 10,000 gallons raises free chlorine by 1.5 ppm. Re-test in 4 hours.
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