You pretty much have to drain the pool.

You pretty much have to drain the pool.

High cyanuric acid (CYA) is basically a one-way street. There’s no chemical to break it down, no filter that catches it. The only reliable way to lower CYA is diluting the water — meaning partial draining and refilling.

Some people claim reverse osmosis trucks can remove CYA without draining. They work, but they’re expensive and not available everywhere. If that’s an option in your area, it’s your best bet for avoiding a full drain.

You could also try topping off with fresh water after backwashing, over weeks, to slowly lower CYA. That works if you’re not in a hurry and your CYA isn’t sky-high. But it’s slow and uses a lot of water anyway.

Bottom line: if CYA is over 100 ppm and you want to swim soon, call the RO truck or start draining.