Well Ben,
If you want cheap do what I do. I use a small airstone to break up the CO2. THe stone is actually in the input of the filter. I use this technique on a Fluval 104, which youa re not supposed to do since they can be prone to air lock, but it works great because the airstone breaks the bubbles up enought initially that by the time it gets to the impeller of the filter they are completely dissolved. I get 100% saturation this way and it was very cheap. I use the Lee brand replacable kind. They are white, about 2" long, made of plastic and the "stones" themselves slip over the connector to the airline tubing. They are easy to cut shorter (cut off of where the insert goes, not the other end
) if space is limited. I just removed on of the plastic strips from the bottom of the strainer and I use the airtubing/stone connector joint to hold it in place. Works good for me
If you want cheap do what I do. I use a small airstone to break up the CO2. THe stone is actually in the input of the filter. I use this technique on a Fluval 104, which youa re not supposed to do since they can be prone to air lock, but it works great because the airstone breaks the bubbles up enought initially that by the time it gets to the impeller of the filter they are completely dissolved. I get 100% saturation this way and it was very cheap. I use the Lee brand replacable kind. They are white, about 2" long, made of plastic and the "stones" themselves slip over the connector to the airline tubing. They are easy to cut shorter (cut off of where the insert goes, not the other end