Inker, with the Bio-wheel, the biological filter is in the wheels so it helps keep it there even when changing the charcoal filter.
I currently run the Emperor 400 on my 55. The advantage of the Emperor over the Pengiun is that it has 2 chambers that flow water thru the charcoal filters and also adjustable spray bars to keep the wheel wet. It also has a second filter that allows you to add additional charcoal to help eliminate ammonia. I'm very happy with it, and will never use a different system.
Skiltrip, the 280 would work great on your 37.
I currently run the Emperor 400 on my 55. The advantage of the Emperor over the Pengiun is that it has 2 chambers that flow water thru the charcoal filters and also adjustable spray bars to keep the wheel wet. It also has a second filter that allows you to add additional charcoal to help eliminate ammonia. I'm very happy with it, and will never use a different system.
Skiltrip, the 280 would work great on your 37.