Planted Tank Guru
Join Date: Aug 2007
Location: Hendersonville, TN
I highly doubt the pump will create enough suction to extract the yeast mixture (C20 FTW!). It is possible, and you'll know within a few hours of trying.
Back when I was doing the DIY yeast CO2, I ran the airline tubing into the intake of my XP2 filter. That worked pretty well, well enough for a lower light tank.
If you do feed the CO2 into the pump, you do want to make sure the impeller smashes the bubbles up, so introducing the gas before the impeller in either an intake strainer or other orifice is best. I have used a needle wheel type pump, made by Gen-X (the 1000 l.p.h. model), and had very good results with it. There is also some good information around on modifying the impeller of a regular powerhead to break up the bubbles more efficiently.