I could swear I saw someone with this same problem, but maybe it was over at the PF site? Anyway, everytime I do a PH test, I get a different reading if I do it twice. For a while I was testing FC first, then PH, and that's when I noticed the problem. Then I thought, maybe I'm not rinsing well enough. So I am now doing the PH test first, but it still does it. The first test is ALWAYS lower. For instance today, first test was 7.2, then did it again and got 7.6. A couple of times it was 7.0-7.2ish the first time, and 7.8 -8.0ish the second time, which is WAY different! I'm trying to figure out if it could be the dropper tip, but it really doesn't look like the drops are a different size.
By the way, if I do it a third time, I get whatever was on the second test, so I'm assuming the first test is incorrect.
Anyone else having this problem? Should order a different reagent bottle?