Should I have a bag of carbon in my chamber? I don't have anything in the middle chamber of my biocube. The water only gets about 3" high and about the same in thd 3rd chamber where the pump is. I have my heater in chamber 1 (the inflow). I have filter floss in the little area before the pump where the blue sponge was. Also if I was to get a protein skimmer, how deep does it have to be submerged? and would I be able to get a HOT one and still keep the hood on?