Needed to vent tank and this is how I did it. 
Carbon filter material 
Some activated carbon from local pet shop
Co2 cilynder
Micro filter 
2x 1/4" bungs 
Aluminum tubing ( placed some carbon mesh inside ) to prevent clogs 
Line going to tank is isolated from loose carbon. 
Access on top to replace carbon if needed 
Will put a safety valve on the line 
 
 
 
