Normal
I haven't used sand (although I think that the top soil I buy usually has some sand in it) but I like mixing vermiculite in my my topsoil/peat for better water percolation and moisture retention. Still, many folks use pure peat or soil without incident (I just enjoy mixing different soil types for desired properties). I have moved away from coco fiber for my moisture loving species. It absorbs water well and quickly, but it's quite fluffy and tends to dry out much to quickly for my tastes. If you use that with those critter keepers, you will just have to be extra diligent in keeping the soil moist.