Advice? Hanna Alk Checker

You multiply that by 0.056 to get dKH so that's 7.896 and 8.288 so I don't know if I would say that is extremely different.

The accuracy range is +/- 5% of reading (ppm) which is about 7ppm for that reading so both are within the range of expectation. Little differences might be due to variations in the cuvette but that typically only shows up on the ULR Phosphorus test. Sample size can vary it too, I always use a syringe to measure the water out instead of going by the line

 

I ignore the line completely but I think yes, above the line. My experience with API kits shied me away from trusting any lines. Because, where do you fill to, the point where the water is just touching the line (capillary action up the sides) or the lowest point of the water? Too vague, for any kit.

Also when you are adding the reagent, I do this very slowly. The little syringe attachment thing they give you is great, but if you go too fast, some of the reagent clings to it. If you go slow enough, this doesn't happen. Sample size + reagent added, if these are consistent, you should get more consistent readings.

Also don't shake the cuvette, just tip it back and forth 5 or 6 times

As with any Hanna Checker, wipe off the cuvette before you insert into the tester (for calibration and testing) and use the same cuvette for both steps (don't use one for calibration and one for testing)