Keep your saltwater pool’s CYA between 30 and 50 ppm.

That’s the range to avoid chlorine lock. CYA (cyanuric acid) protects your chlorine from UV rays, but too much of it—usually above 80–100 ppm—binds the chlorine so tightly it can’t sanitize. That’s chlorine lock. Saltwater generators produce chlorine slowly, so you don’t want any of it wasted or locked up.

Test your CYA monthly with a good drop-based kit (test strips are less reliable). If it’s under 30, add stabilizer (cyanuric acid) according to the label. If it’s over 50, especially over 80, the only reliable fix is to drain and dilute. There’s no chemical that removes CYA. For a saltwater pool, aim for the lower end (30–40) because the generator is always making more chlorine—you don’t need as much UV protection.

A little math and patience beats fighting algae all summer.