CO2 and Filters

I've read in this newsgroup (haven't bothered looking it up) that motion on
the surface of the water will deplete C02 levels in my fish tank. Does that
mean that if I inject CO2 into perhaps an AquaClear filter's intake (the
kind that hangs on the back of the aquarium and trickles the water back in)
that all the CO2 will dissipate before it even reaches the tank? What if
the CO2 was injected into the bottom of the aquarium and was then filtered
naturally? Would the plants even have time to utilize the CO2 before it
dissipated into the atmosphere when going down the little "waterfall"?

I just started thinking about this when I decided to plant one of my 10
gallon tanks that has an AquaClear Mini. Thanks for any info anyone can
provide.