I use a mix of miracle gro organic potting soil and organic topsoil mixed 50/50 for my 2" base nutrient for my plants to grow on, and then 1.5" of sand over that to lock it down. My plants grow and grow, without dosing anything. I use an algae scrubber for filtration, and to keep the algae from growing in my tank. I do use a diy co2 to add co2. I also added a couple pinches of steel shavings from behind my bench grinder to the base mix for a lil iron too. In my opinion, plants should grow out of dirt... not gravel.