dont need sand or gravel. they float or get put on rocks or driftwood. with a sword i would put it deeper. a lot of people start at 2-3 inch in the front and put 4-5 in the back.
yeah i know about not needing sand or gravel, i was just copying and pasting from when i said it before . Id rather have all the tank at the same level of sand since my cories or loaches (depending on what i get) would probably end up evening it or my gravel vacuuming may even it out as well) except maybe make a cliff out of slate rock into a shallow sand bed where i will put the non rooting plants like the moss and fern. So i'll probably go with 4 inches.
Should i use this? http://www.aquariumguys.com/purelaterite.html
Following the instructions i will have a bottom layer of 1 inch of laterite and sand, then a top 3 inches of just sand. Is that good or bad?