I've got a Hayward de4820 de filter. I cleaned the whole thing before putting it away for the winter. I opened it and looked at it before starting the pool this season, it looked ok so I closed it back up. I started vacuuming the pool to waste and had problems with the vacuum (there's another post I put about this). While trying to diagnose the vacuum, I ran the pump with water going through the filter and didnt add any de. I figured I'd have to clean it quickly because of all the junk from the vacuum. While trying to figure things out, I found the manual for the filter and it says not to run the filter without de for more than 2 minutes. Wish I would have found that sooner. So did I screw things up? And if so, how do I fix it.
with the the pump running and trying to vacuum, the vacuum doesn't work well and there's very little water coming out the jets. I'll try disassembling the filter tomorrow and spray it with a hose. Pressure is almost 20 psi. When I put on recirculate, pressure is 10 psi and good pressure out the return jets.