Epsom Salt Question For Coco Coir

I used to put cal mag in the mix with my canna nutrients but now I ran out and don't feel like buying more since I could just get a huge container of epsom salts at Walmart. I would like to know if any of you have used it in their coco coir, what amounts to use, do you mix it in with the coco or do you mix it in the water. Why do you use the amounts you do, etc...

Thanks in advance, lookin' forward to some feedback on this.

Calmag adds nitrogen (nitrate N) calcium, magnesium and iron. Epsom just adds magnesium and sulphur.

I read somewhere to add 1 teaspoon per gallon. I think it was when I was looking for calmag substitutes...I just bought calmag.