It sounds like your filter is working like it's supposed to--maybe the DE trick will help it get the finer stuff. I would hold off on the EcoKlean substitute until Ben or one of the equipment guys says it's okay--some of that stuff gunks up the sand to the point where you'll actually have to replace it, and I'm not sure about that one.

I guess it's possible that the pump is pushing too much water through the filter--I have the same filter you do with a 1 HP pump on it--but again, I'm not an equipment pro, so Ben, Mark, or one of the others will have to take a stab at that one. I would think that if that were the problem, it would also be pushing sand and other debris back into the pool. IN the meantime, just keep the filter running and backwash it as you need to. Remember that a dirty filter works better than a clean one, so I wouldn't backwash it until the pressure is at least 8 psi over "clean".

How does your water look? I know it's cloudy, but is it blue? Green?