Open Pool, Shocked But No Chlorine Level

[karenk]

Hi,
Hubby opened the pool yesterday (15 x 24 above ground)....water nice, just a bit cloudy. I did see him scrubbing the ring around the liner with the squeeze bottle/scrubber remover..and he also used an algecide.....then he shocked it with liquid chlorine....took a read out and showed "0" level of chlorine....so he put the powder chlorine in and same "0" reading...

I saw in one of the "hint" pages this..

Try to avoid using a bunch of foamy algaecides or foamy tile line cleaners. These can create a chlorine demand in your pool that won't quit. This means you'll add chlorine, and add chlorine, and nothing will seem to happen. This is NOT A GOOD THING. [/SIZE][/SIZE]


How do we adjust so that we can build up the chlorine level...don't remember this happening last year!! )

[aylad]

What kind of test equipment are you using?

Janet

[karenk]

We just use those test strips in the bottle...we have used them for 5 years and never had a problem. (I know some people like the more "professional" testing method, but we are pretty much sticking with the strips).

How much chlorine should we be adding at a time now to build the chlorine level...do we still use the regular 'shock" some say "super shock" envelope packages to dump in or is that too much at a time?

[aylad]

How much chlorine you need to put in to get to the shock level depends on your current CYA, which you haven't posted yet. And I know that you like the strips, but just understand that they've been known to be pretty inaccurate, especially with high chlorine levels.

Depending on the other parameters of your water (pH, alk, CYA, CH), you could use bleach, shock, "super shock", or the chlorine method of your choice. Trichlor and dichlor are going to lower your pH and raise your CYA. Cal-hypo won't affect your pH or CYA but will increase your CH levels. Bleach won't affect anything directly except your Cl levels. Whatever form you use, add enough to get to "shock" level based on your CYA (see Ben's Best Guess Chart as a guideline).

Janet

[gregugadawg]

Janet actually 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. Some health departments are actually allowing strips to be used in commercial applications as well.

[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...