Thanks for the nothing sacred advice. I suppose as long as you don't get rediculous with the DE, more would be better. I will say that I am amazed at how bad the filtration of the sand unit is compared to my old DE one. Yeah, backwashing is "nice", but I have to backwash like crazy if the pool is really dirty (like pool opening) and backwashing uses a TON of water. With the old DE unit, I'd clean it once a season and it would be fine aside from the fact that it filtered like crazy.

Part of the reason for my buying a robotic pool cleaner was to supplement the sucky filtering of the sand unit. Well, I guess I'll see if I can pick up some more DE today unless I still have some hidden away in the garage.