Dean Cook

We typically use decomposed granite. I never thought of using sand. I don't see anything wrong with it. I might put a layer of rock around the tank, on top of the sand, to prevent erosion. It all looks great though.

Hi Wayne. Nice installation. (Both). We have come to the conclusion that in a lot of circumstances the first wash is not necessary. Partly depends on what the water will be used for, and how much debris and leaves end up on the roof. We have never tried using a sand base. How's that working out for you?