Hybrid - What if I made a substrate out of two materials. So the more I read the more I see oh do this.. Or this is better than this and that works but you need root strips and this will break down.. What if I did a combination of topsoil and something else like clay or eco complete with the dirt so that it will have plenty of nutrients and then it will also have something that can absorb and slowly release them over time. This would mean I wouldn't need to replace the dirt in the tank. Any thoughts? Thanks.