Are there any tests that interfere or have to be accounted for when testing CYA? Like calcium, etc?
I tested the CYA of my dad's pool to be 160 ppm. I bumped the FC to 18 ppm, the target percentage, but it keeps dropping to 8-10 overnight and through the next day. No CC and the water is crystal clear, but it does have the pollen problem many others are reporting. I'm finding it hard to believe that it's losing 8-10 ppm of FC just to pollen, though. No one's been in the pool for a week.
When I took over, the pool guy had royally screwed up the pool, turned it to green soup, eventually replaced the water then let it go to. No idea what he'd been shocking with, but obviously dichlor as there is CYA (plus there was a case of it in my dad's shed which he's since returned), and I suspect he also added straight stabilizer. I'm now wondering if he also used cal-hypo and possibly it's accounting for some turbidity that I'm reading as CYA, and possibly the CYA isn't as high as I tested. Pool does appear clear though, you can easily see the bottom 4' down.
Just wondering. If it is really 160 CYA, then it's likely pollen that's eating the bleach. If it's not, then I'd like to know so I can quit donating bleach to the sun