Sorry...I don't know how it would convert...you'd have to experiment a little....or maybe someone else here can offer suggestions. I've drunk a bottle at once prior to a flush and that was sufficient to clean me out...but then used colonics for follow-up after the flush. My guess is a bottle...10oz, I think...is probably about equal to one dose of the Epsom Salts ...but don't hold me to that!
Another option would be Freelax tablets...they're magnesium hydroxide... but again I'm not sure how the dosage would convert.