Open Pool, Shocked But No Chlorine Level

[DavidD]

test strips are being proven to be more and more accurate and sometimes actually they are considered more accurate than the drops since there is no level of human error involved.

gregugadawg, that's a pretty broad statement. I'd like to see the “proof” you are referring to. Health departments also “allow” a lot of other things and make recommendations that are entirely out of date so I wouldn’t be too trustworthy of their allowances . I have and still do buy test strips and must admit they seem to be getting better however, accurate? I think not. Unless you believe a color match for PH between 7.2 & 7.8 is good enough or TA between 40 and 120 is an accurate enough reading or CYA between 50 and 100 will get the job done. Maybe you’ve hit on something, they remove the human error by being extremely vague. Seems to me it would be hard to truly manage your water with such imprecision. Now I know there are new strips with tighter scales but more accurate, I still wonder.
What Janet is saying about the strips being inaccurate with high chlorine levels is absolutely the truth. They will bleach out and it has happened when people shock their pools, test with strips and believe they need more shock when actually they are outside the range for the strips they are using. This may very well be what karenk is experiencing here. Drop based test kits, good ones, are far less intimidating than they appear (my kids are testing regularly) and their accuracy is unprecedented, especially DPD testing of chlorine. They take slightly more time to do a test but isn’t it worth it? I’d hate to keep adding chlorine to karenk’s vinyl lined pool then keep searching for the chlorine that will probably never show up until the liner starts turning white. Either way, the decision is entirely up to karenk. The one thing I have yet to hear is regret that someone spent the money on a good drop based test kit.

Note:I see the test strip "issue" has already been addressed by Waterbear, a far more chemistry minded one than I, in the Princess and the Algae post. I digress...