Magnesium Question

[somewherebeyondthesea]

I'm wondering if there are any test kits around edmonton for Magnesium?

I'm not sure my levels of magnesium are adequate, I know they do get replenished when I do water changes. My Calcium is adequate so I'm not too sure?

One of the reason's I am asking is that I'm having trouble growing certain SPS corals while others are thriving?

If anyone has some ideas to add I'm all eyes!