Are these the Dumbest Trochus snails ever!

[Deezill]

Is there a good mag test you recommend? I have hanna checkers for calcium, phosphate, nitrites, and alk as well as API test kits and some test strips but I don't think any of them measure Mag, which kind of made me think it wasn't overly important. I got the hanna checkers after realizing that the API test kit and test strips weren't very accurate for me.

I use salifert