All these test options are making my head explode!

[Junkmanthom]

I wouldn't recommend the Hanna Calcium test. There is a 100/1 dilution that makes the test inaccurate. I didn't find the Hanna pH meter to be reliable no matter what I did.
I use Nyos for NO3 and Salifert for everything else.
The API test kit is cheap for a reason.

Hmmmm... more to think on! Thank you

 

[Erick375]

Also because no one has mentioned, frequent water changes with high quality salt helps more than anything in getting good quality read outs. I have several of the Hanna meters and like the “numbers“ results, and to someone’s earlier point about their calcium, if I get an odd reading I just redo it assuming operator error.