Quote:
Originally Posted by reefwars
not needed your system is perfectly capable of breaking it down with a cuc ( clean up crew) like crabs,worms,snails,urchns,pods ......you can leave the sponge but it would need to be rinsed very frequently or it ruins the risk of hosting ditrius and thus creating nitrates which in turn fuels yoiur algae  |
I ran a canister for 4 years before upgrading my tank, and as long as you do regular maintenance on your filter, as Denny said - clean the sponge, it should be fine.
I NEVER had nitrates/nitrites present in my 20 gallon while running my canister. I am a believer in some sort of filter to catch large particulates (poop, etc). I even run a large sponge in my sump now and would never do any different. It helps keep my sump looking pretty (not that a sump needs to look good - hahaa)... but I would not worry too much about it.
If you start having an issue with NO2/NO3 then perhaps you can address whether or not the sponge is the problem. Just clean it regularly.