Is Magnesium Testing Necessary?

[ScurvyFrog]

I regularly test my system for Alk, Cal, PO4 etc. My question is - If I am using the same salt mix (Pro Reef), dosing (All for Reef), and the parameters for salinity, Alk, Cal, PO4 are remaining level - is it safe to presume that magnesium is in decent shape too?

I am happy to pick up a Hanna checker for mag, but I have heard that mag testing specifically can be inconsistent.

Would love yalls thoughts on the topic.

 

[Lavey29]

I only really test it about every 4 months or so with an ICP overall test. If you are doing weekly water changes with a quality salt then magnesium should be fine. I dose 15ml of mag weekly because I do water changes every 3 weeks now so it's just dosed between water changes. Mag only depletes at 1/10 th the rate of alk consumption.