Test readings

[nicknac]

When I take test reading with my aqua chem test kit it tells me to take a sample and drop 5 drops in each tube. Compare color and after 5 minutes compare color for total chlorine level. My question is my total chlorine level is good at 5 minutes, but after 30 minutes to an hour the chlorine is all gone. Is this normal or does this mean I need more cyanuric acid to stabilize or shock it??

[lbridges]

Not to worry - that's normal.

[chem geek]

The chlorine tests are designed to be read within a minute or so and not to wait. However, the test kit you are using does not have the best chlorine test available. The best test kit is the Taylor K-2006 you can get here. It uses a FAS-DPD chlorine test where you count the drops and can measure accurately to within 0.2 ppm using a 25 ml sample or to within 0.5 ppm if using a 25 ml sample and can measure up to 50 ppm so is useful when shocking.