I have a very cloudy pool due to lots of dead algae. I purchased a new DE filter, and I had to bump it every 20 minutes or so. After about 3 hours, the pressure will shoot right back up to over bump pressure within a minute. I backwashed and added new DE, and had the same result after another couple hours. Is this normal? Should I expect to go though quite a bit of DE? My filter takes 4 pounds of DE at a time.