You'll save a lot of reagent if you test your chlorine at the 10ml level instead of the 25ml level. Then one drop = .5ppm instead of .2
For 99.99% of chlorine testing the .5 level is as close as you EVER need to be. I may have used the 25ml/.2 level twice in 10 seasons, and it must be five years since the last time.

Carl