I thought the ratio was opposite - double the mag to the calcium? I'd been supplementing with food form (megafoods or garden of life) cal/mag, and added extra mag when when I was having more cramping, but turns out I was not absorbing most or any of it, as I found out through blood testing I was really low in both magnesium and potassium (along with sodium, iron and vit-D). I put off that testing a long time, as I was sure my levels had to be good, given all the supplementation. My situation started out with restless legs for 5-7 years, then progressed to more tiny muscle twitches and then severe cramping in my legs and feet. I'm now getting it intravenously once a week for awhile, and topically with the mangnesium oil until I get my levels back up. What's weird is that the restless legs stopped once they started tending toward cramping and heaviness every day (there's a circulation element involved for me, also), but I've had a few RLS episodes recently, almost like I'm progressing backwards as the cramping improves. Crazy. I don't know if that's a good thing or a bad thing, though I know my levels are still low. For me, I need to get my gut healed up, apparently, so I can absorb the mag and potassium I need from food, or at least supplements. Also, the low sodium could have been throwing off the whole electrolyte balance and part of the reason for poor absorption, too.