AquaChek 4-in-1 Free Chlorine Test Strips for Swimming Pools

AquaChek Yellow is the four way test strip for chlorine pools and spas. One strip reads free chlorine, pH, total alkalinity and cyanuric acid, the four numbers that decide whether the water is sanitized, comfortable and stable. There are 50 strips in the bottle, enough for a season of weekly checks.

How it works

Dip a strip, pull it straight out and hold it level for 15 seconds without shaking. The pads change color, and you match them to the chart printed on the bottle, reading pH, free chlorine, total alkalinity and stabilizer in that order. The whole test takes well under a minute and needs no reagents or vials.

Why the stabilizer pad matters

Cyanuric acid protects chlorine from sunlight. Outdoor pools and spas lose chlorine to UV all day, so knowing the stabilizer level tells you whether the chlorine you add will stay put. For the most accurate stabilizer reading, keep pH between 7.0 and 8.4 and total alkalinity at or below 240 ppm.

Keeping the strips accurate

Snap the cap shut as soon as you take a strip out, leave the drying agent packet in the bottle, store it at room temperature and use the strips before the date on the cap. Test weekly and jot down the results so you can see changes over time.