Sponge filters

[Lkittredge]

Curious how many people that have been keeping CRS for a longer period of time (say a year or more) use just a sponge filter. Currently that is all I am using and after several months it is going well. I don't plan on changing it under the "if it ain't broke don't fix it philosophy" but curious if there are some pitfalls people encountered that I should keep my eye on.