One of the most common things I come across when doing a DE filter clean is a build up of DE powder clogging up the filter causing potential damage to your filter. This is caused by 1. Adding too much DE (Always refer to owners manual or label on filter for recommended amounts) 2. Improper backwashing. Simple solution…after you go through your backwash cycle, repeat two more times before recharging your filter with DE. Note, the length of time your filter is in backwash mode being 1 minute or 10 minutes has little effect on how much DE you are purging out of your filter. Once the sight glass is clear on your backwash line, that portion of the back was is complete. Repeating the bw process will clear more of the DE powder reducing the risk of a clog.