Just C33 sand, no other filters, just pump the FT water right on the bed with furrows. Maybe 8 times a day and no nights. The fish poo creates a layer on the sand and breaks down over time releasing stuff to the plants. I have everything I need except the sand. it is worth a trial unit if you have an extra one open. Other then that I am still working on getting educated with it also. I am getting this info on another forum that has a few people that are doing it and have tossed out standard media for sand. The sand needs to be free of carbonates or Ph will go crazy. Granit sand will work up to 5mm in dia and smaller pieces. Washed free of dust and set into a GB and furrowed. Or in a round pail and lumped in spots. The sand should trap everything 100%. I am currently asking if that might cause an abundance of N in the plants and hurt children. It will be a wait. In the meantime I have 2 units waiting for sand.