Well I did what gf225 did.
I am assuming you have pressurized co2. Even if you have yeast generated, just take your co2 tubbing and put it straight into your intake tube of your external filter.
gf225 did his by cutting a hole in the middle of the tube and just inserting the co2 tubing right in there. So the bubbles would just come out and get instantly sucked by the intake.
I did it the lazy way and just took off the ending on the intake tube. The ending with the slots so that big junk doesnt get into the filter. I cut one of the plastic slots out and it was enough room to squeeze the co2 tubing into it.
Same principle just a different area. I also used suction cups to have the co2 tubbing run pararel with the filter intake. It looks nice and clean and its cool to see co2 bubbles fly up. zip zip zip.
Good luck.
