rustyhooks

We just bought a new pentair DE ilter last year and its been nothing but headaches. My main issue is that it gets full in a day or 2. (pressure gauge climbs to like 20)n I'll open it up and sure enough, its all nasty and clogged to hell. We had the type with 4 lrg filter elements before,...kicking myself for bying this thing. ANy help as to why it clogs so quickly?