If there is no leak, what bubble counter do you use?
The JBJ type push out bigger bubbles, one bubble equals several on that the ADA inline type.
The reason for this, is a bubble double in diameter, the volumn is 8 times of that the half size bubble(in diameter).
I use the bubble counter that came with my Aquatech regulator. It is kind of small and I have really stopped using it as a reference point. I'm hoping the drop checker will work. I might just move it to the side of the take where the return is and see if that makes a difference. Wouldn't think so since the DC is covered in co2 bubbles.
therein lies your problem. the input should be on the top, output on the bottom.
To take the a step further. The flow should be moving downwardly through the reactor. The air bubbles want to rise to the top. As the water flows down the turbulent friction pulls the bubbles down. The counter flow of bubbles wanting to rise but being dragged down causes them to dissolve.