Don't know about crushed stone, but we bought our tub in March, and it rests on pea stone. We have a base under the whole patio area of limestone fines, which compacts almost like concrete, and over that we have 2"-3" of pea stone under the tub. I was originally concerned about the warranty if I put it on pea stone instead of concrete, but the dealer (Jacuzzi) said it was fine, and that he liked this better than concrete because it self levels itself under the tub, and provides great drainage. For what it's worth...
