As my centerpieces, I'm doing 3 different sized cylindrical vases with flowers submerged in water, with crystal vase filler and floralytes. Does anyone know how much filler I will need? They seem to come in 1lb bags, and I have 30 vases total. I am thinking I will want about 3 inches of filler in each... but no idea how much filler to order! Anyone have experience with this that can give me an idea?