Injecting co2 into canister filter

["Kinney, Travis" <kinney at pdtarchs_com>]

I've been injecting co2 into my canister filter for a couple months now.
Seems to work great. I don't understand how you could loose co2 in this
setup, unless something is consuming it in the filter media. The co2 will
travel through a closed system with no contact with air until it exits
through the spray bar and floats to the aquarium surface. I had to cut a
little section out of the plastic intake filter thing to fit the plastic tub
into. Bubble comes out of tubing and gets sucked up into filter. There is
some noise caused by air building up at top of filter and churning around
the impeller, but I figure it is just helping to bust the bubbles up. Ones
in awhile I tilt the filter to let the bubble out.