Just after opinions about the factors that could cause a CH variance between 2 test kits (both Taylor) using the same water.
I've just started testing my CH with my new K-2006 kit and coincidentally found a pool shop near where I live that also uses the exact same Taylor drop tests to do their free testing. I took a sample to them to compare my results with theirs. I was honest about what I was doing and the girl in the shop was really helpful and let me watch exactly how she was doing the tests.
Now I know I'm splitting hairs here, but I got 230ppm and the shop got 210 (even after a second test to check). All other test results (FC, TA etc) were identical to mine. I re-tested with my kit when I got home and still got 230. Can anybody think of any reason that this would happen? I'm seriously not concerned about the 20ppm difference for my pool's sake, but I'd like to know for curiosity.
The only thought I've come up with so far is slightly different drop size? Maybe my bottle has a minutely smaller hole...