I used for almost two years a Pro Clear Aquatic System model 75 Wet/Dry filter in a 40gal long tank with DIY and later pressurized CO2.
Here's a the link to them
http://www.pro-clear.com/wetdry.html
I had no problems other than algae growing in the intake overflow (box placed inside the tank). What I liked about this particular model was the "quasi enclosed" compartment where the pre-filter tray is placed (where the overflow hose goes).
I know I got regular readings of 24-26ppm of CO2 when running it. I redo that tank and dismantled the Wet/Dry for no other reason than the ugly algae growing in the overflow box.
I don't know if this is important or not (as far as degassing) but my unit is an older version that has the incoming water hose attached to a lateral wall (not the top wall) of the Wet/Dry.
Pepetj
Santo Domingo