Thanks Aqua! This is looking better all the time
"Aqua" wrote in message
...
I've followed the basic idea -
Flow input to a vaccum from a gravel cleaner -
bio balls
sponge at the bottom.
1 bubble per second

Problem is the canister fills with co2 - like an air pocket of Co2 -

Is this because there is not enough water flow or ?

First I thought of Doing It Myself. But later I found a cheap internal
filter DJ50 (US $12.00).
It has a airline inlet which is for mixing air with water. I am injecting
CO2 in it.

http://www.dlink.org/aqua/CO2.html