Donnie,

Great minds think alike. I did exactly the same thing after you posted your CH results. Like you, I found that chlorine tests did not appear to be temperature dependent. In fact, the chlorine test seems to be TIME dependent where waiting too long to do the test has the chlorine level drop so it's more important to do the test quickly than to have it be at room temperature.

I did not get the same results as you did with the pH test. I found the pH to drop as the water warmed up and that is actually what I expected since there are technical reasons that should be the case. It doesn't drop that much, however, since it theoretically is only around 0.1 unit from 50 to 70, but from 45-50 to 85 it should be around 0.2 units which is much more noticeable. I heated the sample in my hand to simulate "heated" pool water and got the pH to drop more noticeably (I also kept the container covered during the test to prevent "natural" pH rise from outgassing).

I also didn't find as much variation as you did with the CH test. I did find a small variation, but only a couple of drops difference (i.e. 20 ppm) which isn't much.

I am somewhat conflicted regarding recommending that ALL tests be done at room temperature. I think the pH test is best done at actual temperatures since pH is supposed to vary with temperature and the chlorine test loses accuracy if you wait too long. So perhaps, all tests but pH and chlorine should be done at room (or "warm" water, if in the summer) temperature or if you let water warm up for the chlorine test -- cover the container while waiting.

Richard