Im no expert, but i set up my tank a few months ago and for several months beforehand i researched like crazy and read countless forums. You will read a million opinions on what people think is best, all i can say is what i did which was miracle grow organic topped with play sand. i couldn't be happier with my choice. Super inexpensive, and the plants love it. Also the play sand looks great, especially if you want that natural look. I tossed in several various types of broken shells collected in florida and a few handfuls of crushed coral i had left over from another tank. I love it. Hope my experience helps. Good luck.