"Dave Millman" wrote in message
...
wrote:

I disagree - I use a block of filter foam over the intakes of my Ehiems.
Medium planted tank (90 gallon) medium population. Every water change
(weekly) clean the prefilters. easy.

Graham Broadbridge )
wrote:
Q. What does pre filtering achieve in a normal
: planted tank? A. Daily cleaning of the pre-filter :-)


I'm with Graham on this one. My cannister is up to three months between
cleanings.
Prefilters clog fast, then faster with age.

I don't let my filter get that old though. I clean it weekly just to remove
the amount of crud it picks up, such as small bits of plant which decompose
and add phosphates back into my phosphate free tank :-)


Graham.