CO-2 injection into a canister filter.

I've set up a Yeast CO-2 system and have been toying with different ways of
diffusing the gas into the tank.
Last night I hooked the CO-2 line directly into the inlet of my canister
filter.
I was going to set up a powerhead and airstone as per a couple of websites
but thought that the canister filter method would do a better job.

It seems to totally pulverise the bubbles into the water and still run
silently.
I can't see any gas bubbles coming out the submerged filter spray bar so I'm
assuming that it's totally dilluting the gas.
As the filter is a totally closed system I also can't see anyway that the
gas could not be injected into the water.

Has anyone tried this method and or am I barking up the wrong tree?