I have used Salifert tests for calcium for some time. I recently decided to try a Tropic Marin kit. My tests differ by about 20 points - with the Tropic Marin test yielding the higher results.
Do any of you have experience with these and have a feel for accuruacy and consistency?
I use salifert and try to maintain my calcium around 450. Personally I would not worry about a 20 pt difference unless that 20pts puts your out of the range.
Thanks. I will probably go back to Salifert - perhaps before this kit is exhausted.
FWIW - i ran the test today on the little nano in the office where the lights are brighter. The test requires that you add a solution until the blue color disappears. The very last bit of blue may difficult to discern (even with the separate vial of water used as a control) - especially if the light is not high. That could be accounting for the difference.