Can somebody help please?
I have a canine Hydrotherapy pool which holds 9,000 litres (2,000 imperial gallons). It is indoors above ground and made of Polypropylene and has a sand filter. The pump will circulate the water volume in an hour but obviously takes about 3 - 4 hours for complete water turnover.
I have to admit however that the pool is not running 24/7 as I do not have dogs in every day for rehab. One day a week it is not on at all.
The problem I have is that I have over the last week the combined CHL going higher than it ever has done. It is normally under 1.0 but is now at 1.66 and rising. Free CHL is supposed to be between 1 - 3ppm for dogs in this pool. ALK has been a bit low and I have just managed to get it up to 104 today. I like it between 80 and 120. Water hardness has also been a bit of a problem and today it is at 172 although I would like it higher I will be adding more calcium in the morning.
I use chlorine granules which I dissolve in a bucket of warm water before emptying round the edges of the pool. The water temperature is a constant 29.5 C to 30C heated by a hot water heat pump (very economical!)
What I want to know is how much chlorine should I be adding to this pool to get rid of the high combined CHL levels?
Help would be gratefully appreciated