Hi all,
You'll just need to ensure that the filter sponge is regularly cleaned (preferably in tank water from a water change) to prevent it clogging and reducing flow.
I like a PPI10 or PPI20 foam as well, but I have it on the filter intake, that way it is easy to clean without having to open up the body of the filter.
Basically I want ammonia and oxygen in the filter, and nothing else. You also want to ensure that all the filter media is fully aerobic, which means that you don't want the flow slowing too much in the filter.
Companies are always trying to sell "special (ie. expensive) media" based on the concept that as well as aerobic nitrification, anaerobic de-nitrification will occur in the finer pore spaces. Lets just say I don't think this is a good idea.
You can DIY the pre-filter from a sheet of foam (like below)
or use the drilled ppi20 12" x 4" cubes that they sell for Koi ponds (I usually cut these into 4" x 4" cubes).
After that I just 1/2 fill the body with glass/ceramic rings, Eheim "cocopops" (SubstratPro), Alfagrog, Pumice, Hydroleca, Floating cell media, or more PPI10 sponge.
If money wasn't a consideration I'd have PPI10 Poret foam pre-filter and "coco-pops" as the internal media, but I wouldn't buy either specially if I had other sponges etc to hand.
I've not tried them recently but plastic pan scrubbers are probably just as good.
cheers Darrel