Hi all. I am cycling a 75g bare tank right now. I want to use Miracle Gro Organic Potting Mix and then regular sand on top. If I'm shooting for 2 inch substrate, What should my ratio of the potting mix to sand be? (ie, do I want 1inch for both?) Also is there a specific way I should be putting the stuff in for it to not mix? My tank is full of water with canister filter running.