Is it normal?

[PAGirl]

To not have to add chlorine every day? That might sound like a dumb question, but I went 2 or 3 days (pool wasn't used but I still checked the cl levels in the morning and evening) without having to add any of my 12.5% liquid chlorine. (Pool was covered) My PH runs about 7.2-7.3, CYA about 25-30, and I've been keeping the FC level about 3-5. Water temp is 80-ish, and the water is clear. I don't have one of the big test kits yet. I have been trying to get the hang of the pool calculator, think I understand it pretty well. Mind you, I am not complaining, just curious.

 

[linen]

With a covered pool, assuming the cover is opaque, your low chlorine usage is not surprising. Lack of organics getting in the pool helps too, as does no swimmers

 

[chem geek]

And lower temps help as well. At 80ºF and no exposure to sunlight, the chlorine loss might only be 0.3-0.4 ppm FC per day. At 88ºF it's more like 0.7 ppm FC per day. In the winter at 55ºF I only lose about 1 ppm FC every couple of weeks.