Alkalinity: Hanna checker vs. Salifert accuracy

[a.browning]

Which test kit do you guys trust more? Both give me consistent results, but they vary from each other. Last night I tested 4 times.

Salifert: 10.35, 10.20
Hanna: 9.30, 9.25

So it would seem that Salifert reads 1dkh higher than Hanna. However, I've read other posts where users report that Hanna reads 1dkh higher than Salifert, so I'm confused. Obviously the important thing is stability, which is not the issue, but I'd still like to know which kit to trust. Both kits are new, not expired or anything.

Has anyone had similar findings?

[metalmulisha]

+1 I had the same thing with elos tests and hanna checker. Tagging already along.

[mc-cro]

The reason I switched to the hanna is because I hate titration end points. The exact point of the proper color shift can be different from one person to the next. And I always felt like it was too easily messed up. Heck I can get a different reading if I am standing next to a window, or doing it by the light of the tank in the basement.

With the Hanna, I just shoot for 9.5, I dont care if its high or low, 9.5 is a good middle range, and its exact. (it may not be correct, but by god its an exact number)

[bertoni]

The honest answer is that we don't know. The results from the test device or kit might vary a bit over time, or with reagent batches. Both those numbers are close enough that I wouldn't worry. If you have access to a high-precision scale, I can give you a recipe for a test solution that'd tell you more about what's happening.