I spent several hours tending the pool last Wednesday. I added 2 cups of 10% liquid Chlorine to get the level up from ~15 to 20. High CYA indicates target of 14-21. So then things were busy at work, not getting home until after dark. And Sunday was a full day with some other stuff. This morning, Monday, I checked pH and Cl. pH is dead on at 7.5, same as Wednesday. Chlorine dropped to 10-12. I have to dilute the sample. I took one reading at 1:4, another at 1:5. It indicates I need to add close to half a gallon of Chlorine. Is this extreme?
It has been warm and sunny, 80F, and the pool is in sunlight pretty much all day long. Water temp is 58F.
Is this a normal amount of Chlorine to add, based on your experience, or is something amiss?
PS: Pool is 16000 gallons