on the other hand, my prefilter sponges usually get so gummed up from all the crud, that they end up restricting the flow from the filters and powerheads. i usually clean them thoroughly in the tank+tap water coming from my python when i do water change. i rinse them until no brown stuff comes out. i figure that, between the 2 filters and my substrate, the bacterial colony will hardly be affected by the small loss from the sponges. i have never had an ammonia spike afterwards.
don't turn your back on the ocean.