im usin MG perlite right now, but am about to change it up. Using MG perlite is the same as using MG soil - you can use it, but you have to be careful if your adding your own nutes to the mix, cuz youll be able to burn the fuck out of your plants really easily. Ive burned my plants badly twice now, and they are surviving after a flush and changing out the soil once, but then ive made the mistake of goin right back to MG, using moisture control soil and MG perlite. Burned them again like an idiot tryin to add MG bloom boost to the mix, cuz it says right on the fuckin box that if i use it as directed with other MG products it garuntees no nute burn.
Well that garuntee fuckin sucks cuz i got nute burn, lol. If you can, find some normal perlite at Lowes or Home Depot. They should have it. I found regular Perlite, Vermiculite, and worm castings there, but i didnt buy them cuz im goin up to the hydro shop n pickin up some fox farm
good luck man.