JNW Direct Pool Test Strips for Pools and Spas - 7 in 1 Water Test 100 Pack

Clear water and balanced water are not the same thing, and the eye only sees the first. A strip shows the second: dip it for two seconds, wait thirty and hold it against the chart on the bottle. This one reads seven values in one go – free and total chlorine, bromine, pH, total alkalinity, total hardness and cyanuric acid.

Strips are a guide, not a lab test. Colors are compared by eye and the listing gives no accuracy figure, which is enough to notice a pH that has wandered or a sanitizer reading that has dropped to nothing. The maker says to use an opened bottle within 90 days, so expect to replace it before it is empty.

Tip: Take a strip out with dry fingers and close the cap right away – the maker’s own advice is to keep the strips away from moisture and light.