Ahhh, which one to trust... I know that with the calcium hanna kit, even using medical grade syringes for addition of all reagents/samples, the kit would give me results that were 50-60 ppm off from each other for back to back tests so it requires a precision that I guess I just don't possess.
And I am no slouch in the lab!
Cheers,
John
This would be a good example of one not to use.