Well, these microfloc filters were built like that from the bottom up, but then they were reversed. So you had them fines on fines and then medium and then big ones. Well, the problem comes when you backwash your filters with a large, medium-fine stuff, you backwash at twice the rate of the filtration rate, and that actually lifts the bed and jumbles all of the dirt and stuff out of it. Then as you turn off the backflow, the filter resorts itself according to size and to weight. You can’t put the fines on the bottom because everything would get mixed together. So then the next thing is to build fines on fines. Medium-sized, big-sized, but those things are designed by weight rather than by particle size. So you put if you’ve got silicone here for fines, then you put granite on there, which has a high specific gravity.
