15ppm chlorine?

[mohawk]

How do you test for 15ppm chlorine when closing down the pool? I have only been able to find tests up to 10ppm. The pool store said I wouldn't need to be any higher than that. Any ideas? Thanks alot.

[chem geek]

The FAS-DPD chlorine test can work up to 50 ppm and is found in the Taylor K-2006 test kit as well as Ben's test kit. If you already have a good test kit for everything else (TA, CH, CYA), then you can get the Taylor K-1515-A (or K-1515-C for a larger bottle of drops) which is just the FAS-DPD chlorine test by itself.

The other thing you can do is the shotglass method of dilution which in your case you could to with 1 part pool water and 1 part distilled (or spring) water and them multiply your measured value by 2. Do not use tap water or else you will measure the disinfection used by the city -- either extra FC (if they use chlorine) or CC (if they use monochloramine). You can dilute even more if you want with 1 part pool water and 2 parts distilled water and then multiply your measured value by 3.

However, accurately measuring 15 ppm chlorine for closing is not a big deal. If you add the amount of chlorine you expect will give you 15 ppm, then that's probably good enough. The chlorine will decline over time anyway. The reason to get a FAS-DPD chlorine test kit would be more for next season when it is important to know accurate FC and CC levels.

Richard

[matt4x4]

Well, that's relatively easy to figure out, the test strips show you what you're at before adding bleach, say that reading is currently 0, if it takes 1 gallon to get to 5, then it will take 3 gallons to get to 15.
If you allready have a chlorine reading above 0, you can still figure it out with basic math. If you add chlorine and accidentally get 20ppm, it's also no big deal.
I didn't even bother adding chlorine to mine for as long as i've owned it (when closing), I clean it really good, drain below skimmer and return and walk away, don't bother covering it either. It's allready too cold for anything to grow in it, and all chlorine would be gone over the course of the winter anyways since I don't bother covering and the sun will eat it up, so in spring time it'll be 0 any way i look at it.
I open relatively early, let the vac run for a couple of days to get the dust that accumulated and we're ready to swim.
I really don't understand all the "you gotta do this and you HAVE to do that otherwise beware" attitudes, it's a hole with some water in it that all you have to do is keep clean, yet everyone thinks it's a high maintenance rocket ship!