Hi Haagzilla, I used water with some hydrogen peroxide in it to wipe out my reservoir if there's lots of residue, but I don't do that every time. Sometimes I'll take out the air pump and the air stones when i'm wiping down the res and stick them in the bucket of water and H2O2. I don't want a big buidup of residue on the stones or in the pump.
And I change my reservoir every week.