High CYA

Apr 20, 2018
Yesterday I drained 1/4 of the water and refilled, brought CYA from 110ppm down to 70ppm. I can live with CYA at 70ppm. My question is, can I drop to 50ppm CYA with just doing some deep backwashings over the next year? I no longer use pucks and have converted to bleach. I'm aware of my minimum and target FC levels based upon a CYA of 70ppm. I'm really not wanting to do another partial drain and refill, which then entails balancing the TA, pH and CH again. Thank you. By the way this is not a SWG pool, so my ideal CYA range is 30-50ppm.
Mar 24, 2014
Greenville, SC
It seems to break down by about 3-5 ppm/month anyway, so between that, splash-out and normal water replacement yes, it would probably drop 20 over the next year. Maybe more if the reverse CYA fairy* visits over the winter.

*Sometimes there are large drops in CYA over the winter due to some weird bacteria/ammonia things going on.



TFP Guide
Gold Supporter
Jun 7, 2017
Damascus, MD
Your pool is 20k gallons. Backwashing is 20 gallons or so? The math is not on your side. Your CYA isn't going to dillute much with just backwashing.