Partial drain and refill vs CYA reducer products: Draining is the only reliable way to lower cyanuric acid

CYA reducer products are expensive, slow, and work poorly in practice — I’ve never seen a meaningful drop without draining water. Cyanuric acid doesn’t evaporate, filter out, or degrade with normal chlorine use, so water exchange is your only real option. Drain a third to half the pool, refill with fresh water, and retest. Just check local regulations first.