I know the books all say not to, but I'm presuming they're thinking of the guys who just tosses some sod and sand onto a spot and step on it, thinking it's now solid. If I wanted to properly build up a low spot (about 6", maybe 8" tops), what material should I use (sand / rock flour, soil, gravel with sand or soil on top, other)? I presume I'd need to rent a compactor to get it flattened properly. It would mean a lot less excavating of the rest of the pool footprint (the low spot is maybe 1/5-1/6 of the total footprint of a 24' pool). Not to mention, it would look better. I'd prefer to do this if I can, but I don't necessarily have to.