My mindset goes to large comapnies like Mg,scotts turf, etc that all wanna get your buck for least amount of bang sorta speak. This isnt some hobbyist train set were building here, were providing ourselves and families with medicine,stuff we intend to ingest, so we GOTTA know where our soils is sourced from 100% Mg esp moisture control has all sorts of weirdness in it i choose to avoid because a bale of pro-mix or sunshine mix is FAR superior....why you ask? because they take the time to at least put together a decent base mix you can work with. If you want to make fancy soils,soiless mixes you can, you just gotta do your homework imho