co2 Injecting

[Jrquicker at aol_com]

I was talking to a friend about co2 Injection and told him that I was going 
to start Injecting co2 into the Intake side of my eheim2126 pro11 filter, he 
laughted when he heard this and said that if I did it that way that I would 
kill all the good bacteria in my filter. Well just how do you inject into the 
filter any way? If you inject into the return side of the filter won't you 
lose most of your co2? I need some good advise on this ,and if any one can 
help me out I would be very happy.  Thank You--------Jack