2 Ways to Lower Cyanuric Acid in a Pool

Drain and refill part of the pool Drain about a third to half the pool depending on your CYA level, then refill with fresh water. Retest and repeat if needed. This is cheap and effective.

Use reverse osmosis filtration A service truck filters pool water through RO membranes, removing CYA and other dissolved solids. It costs a few hundred dollars but avoids draining, making it worth it if water is expensive or you’re on a well.