I prefer the 2"-diameter pipe BECAUSE the bioballs are not as tightly packed. :mrgreen: The bioballs' purposes are to increase turbulence as well as prevent CO2 gas from exiting by inhibiting the downward current, both of which function to increase the efficiency of CO2 dissolution. A tightly packed column of bioballs is unable to significantly increase turbulence or trap CO2 gas due to the lack of movement.EDGE said:IMO, co2 should dissolve faster in the 1 1/2" pipe. The bioballs are not as tightly pack in the 2" as they are in 1 1/2"
ADDING CO2 GAS
Ideally, you would want to use a barb for the CO2 tubbing, but barbs that small are difficult to obtain. One way to improvise is by drilling a hole through the top of the reactor and pull the CO2 tubbing through for an airtight seal as illustrated by Rex Grigg. Silicone the surrounding area for increased security. Alternatively, you can use an airline connector as Ghazanfar Ghori suggests. I dislike the airline connector because it always comes loose IME and the connection tends to leak regardless of how well I silicone it.
VENTING FALSE GAS (unnecessary IMHO)
With the CO2 tubbing not connected to the CO2 source, turn the filter on. The pressure will force all the gas (and undoubtedly water as well :wink out the CO2 tubing. Connect the tubbing to the regulator/solenoid/bubble counter once all gas has been vented. This works especially well if the CO2 line is fed through the top of the reactor instead of the side.