Red Sea vs. Hanna

[Seagars]

So i have been using red sea test kits for the standard Alk, Clac, and Mag. I recently purchased Hanna Checkers for the Alk and Calc tests.
When testing calcium i am getting a reading that is some 100 points in difference (Hana higher).
Just wondering what am i doing wrong with either test or what one should i use as the more reliable one.
from a directional standpoint - that has been consistent.
Thanks in advance!!!

 

[mrred]

Hanna has a great video on utube check it out. That test is very particular. 0 ro/di water a must. Also look up what meniscus means and pay careful attention to detail. I have great results from the hanna and it checks accurate with my ap test.

 

[evolved]

The Hanna Ca checker is rather sensitive to an accurate measurement of water being used as well as that water being pure RODI.

I'd trust the titration kit here.