I have done this is the past with moderate success, if you want at least 100% desolution of C02, build a reactor, it is well worth it, and not hard at all, unless one is all thumb's
The filter will accumulate air bubble's using it for a reactor spitting bubbles into tank alot, also not good for the impeller in the long run, if you have a good filter, do yourself a favor..check this out v

http://www.aquaticscape.com/articles/co2reactor.htm