Id go all sand, its very benificial to your fish, easier for benifitial (sp??) Bacteria to grow in sand, as there's waaay more surface area.. here's my tank 20 min. After I did sand (black) the brand was stoney river, and it was all settled as soon as I put it in... nothing gets kicked up, and my maitenence has droped about 35% or so, bwcause of the new substrate. The brand I used (I will forever use this and only this) is stoney river premium aquarium sand for salt and freshwater tanks.