Part II: Fitting the Nano CO2 setup into the Fluval Edge
I originally thought I would need to get a new HOB filter for the Edge because of clearance issues. The pic below shows the HOB filter for the Edge, hung in its stock placement, but without the plastic column that conceals the filter. You can see that the total height of the CO2 tank + regulator is just taller than the space available under the AC20 HOB filter.
However, playing around with the space I figured out a way to make it work.