Trichlor = How much CYA?

[han78216]

This doesn't make sense to me. I moved to a house where previous owner exclusively used tablets for many years. Sure, CYA ended up being somewhere between 240-300 but shouldn't it have gone up to much higher number?

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After the drain and refill, CYA is now somewhere between 70 and 80.
Hopefully this will make it easier for me to keep algaes away. I plan to keep chlorine level between 5 and 10.

[PoolDoc]

This doesn't make sense to me. I moved to a house where previous owner exclusively used tablets for many years. Sure, CYA ended up being somewhere between 240-300 but shouldn't it have gone up to much higher number?

Not necessarily. If he had a sand filter, backwashing and other water loss would limit the upper concentration. But . . . . test results showing 240 ppm CYA are highly suspect. Unless he was VERY careful and did VERY good dilutions, his 240 ppm might have been 600 ppm!