adman

I have a starbright 50 DE filter. I have clean filter fingers and have put fresh DE back in the filter. When the filter is first turned on the water flow to the pool is good and strong. After 5 minutes of the filter running on high the water flow diminishes to a trickle. When this happens I can shut down the filter, bump it, and then restart and the flow is back to normal for another 5 min. I have new hoses, and have greased up all the rings to the filter. Any insight into what the problem could be?