Can I ask why you use perlite ? Since I started using coco, I've been using only coco. When I was using potting mixes, I used perlite for better drainage, but in coco, I can't see a use for it. When your pots got plugged up, It was the DE that did it, not your ferts.. If you put DE on top of perlite, It'll plug that too !! How much longer for the light ? Also, after all the parts, how much $$, for the light. And do i need to be an electrician to build it ? Are you doing a diy for the light, in one of your many journals? Anyhow my friend, I'm waiting to see what this MG is gonna do for us. I'm not getting my hopes up !!