A very thin layer of ground peat sprinkled on the bottom glass under the Flourite helps to start a beneficial bacteria colony in the substrate. And, an inch or so of MTS under another inch or more of Flourite works well as a nutrient rich substrate. Or, you can just use substrate fertilizer tabs to provide substrate fertilizing. Another idea, which I haven't tried, but which has been recommended, is to sprinkle a very thin layer of Osmocoat on the bottom glass, under the Flourite, to get nutrients into the substrate. I am using Osmocoat in riparium planters and haven't seen any problems from doing that, so it should work under the substrate too.