I'm getting rid of my old DE filter and probably will change to a cartridge filter. I have a very small pool (around 12,000g) and am looking at the pentair clean & clear filters. The clean & clear have only one cartridge, while the "plus" filters have four cartridges, but the filtering capability (according to Pentair specs) doesn't appear to be any better. The clean & clear filters are a lot less expensive. Am I missing something? I realize that I would need to replace/clean the filters less often on the plus, but when I do, I would need to clean/replace four filters, so I don't see that as a big advantage.