I also would ditch the bio=balls as a trouble source. Not needed and my big question is due to maintenance. All of my tubing has to be cleaned at times. If I had bio-balls sealed in the reactor, it leaves me to cut it open to clean them and I find no purpose for them if the reactor is sized to meet the filter flow. I use the reactor on the output, let the flow go in at the top., add CO2 near the top and it dissolves before it can get out the bottom.