I preferably like sand more than gravel for planted tanks. But the thing I would actually like the most to use is this type of gravel that petco uses which is their standard sold in store gravels very finely grinded. It is like a rather coarse gravel more so than a sand. Petco uses it in all their plant display tanks near me. This stuff just looks amazing! I really like it and it comes in colors of white and black and maybr more ive just never seen any more. Check your local petco if they sell it as its amazing! It costs $17.00 a bag for a 20 pound bag. So its in the more costy end of substrates. Good Luck!I was wondering if gravel is a better substrate than sand for the growth of plants.