Most of the MG soils come pre-nuted or have those moisture crystals in them. MG that is pre-nuted does not have the right combination of nutrients for cannabis and nutrients are released every time you water. The moisture crystals cause the soil to always remain too moist. Cannabis likes to have the soil dry out some between waterings to bring enough O2 to the roots. I have found the MG fertilizers also do not have the right combinations of N-P-K. Like duck said, you can use it. But, IMO, there are just so many other far better choices out there that it is way way down my list on what I would use. You can always make up your own soil mixture.
Starbuck--This: "...My current nutes for soil are super soil and no nutes till week 2 flower, then FFBBGB with every other water. For dwc I use gh series...."
means this: ...current nutrients consist of super soil (a mixture pre-made and allowed to age with a number of organic substances in it). This provides all the nutrients for the vegging phase. Then at 2 into flower he adds Fox Farm Big Bud and Grow Big with every other watering. If he is running a deep water culture system, he runs General Hydroponics 3 part Flora series.
We can get pretty loose and free with our acronyms sometimes, forgetting how confusing those can be to newer growers. Hare some other acronyms used in this thread: FFOF=Fox Farm Ocean Forest R/O=Reverse Osmosis GH=General Hydroponics FF=Fox Farm.