Quick question:

I've seen it recommended to put a "pre-filter" sponge over the intake of filters. After seeing some of the stuff sucked into my filters recently, I like this idea. Attached is a picture of some common biological foam that I found at Big Al's. Is this the best stuff to use? Also, how thick should I make the layer around the intake of the pump? I thought 1/2" might be good, but not sure.

I would assume that doing this pre-filter, slows the pump down somewhat, especially when dirty. I would expect to take it off at least weekly and wash it out with aquarium water (to avoid killing the bacteria).

Thanks for any advice you can give.

A block of foam etc works fine, I just X a cut into it and slip it over the intake.
Make sure to clean it very often, it'll clog and slow the filter and you can get algae with this effect by self.

So clean it often.

Regards,
Tom Barr