so our 55gal tank has been running since august 09 and we have been doing well. my only concern are these nasty little yellow looking slug things hanging out in our canister fiter. a refugium is in the works, one piece at a time but for now we are stuck with this. are they good or bad, should i be scrapping them off completely? looks like they are also inside the bio balls and sponges now that we just got a t5 light, they are spreading. none are present in the tank at all though. any advice?