On Sat, 30 Aug 2008 22:42:32 EDT, "JB" wrote:

jan - I vote for less often. I do one cleaning of my filter pads every
spring.

This weekend I cleaned both my lily pond & koi pond pre-filters and I
realized why I may have to stick with the design, snails. :-( The koi pond
has the bio-filter to keep them from the pump chamber and they never do get
very big.

The lily pond filter though only has the prefilter to keep snails from the
pump chamber as I have the bio-media in the pump chamber. The ramshorn
snails get to quite the pump-stopping size in there, even with my cleaning
it out every 6 weeks because there are so many in the lily pond that get
sucked into it after I clean. Perhaps once the goldfish get bigger they'll
eat more, but currently I'm not seeing much of a dent in population. ~ jan
------------
Zone 7a, SE Washington State
Ponds: www.jjspond.us