I do not have hands on experience testing this, but I have done loads of research. (mostly from threads on this forum). What I've gleaned from everyone else's research is bringing the CO2 in to the reactor this way makes a huge difference. Bio balls do little if anything.Not to pick at your design here but it is not what I like to see called a Grigg's style as it has some pretty big changes that do matter.
When I add gas at the side it is out of the main flow of the water and it can create problems. When I push/pull the tubing through an undersized hole and let the gas come out in the center of the water flow, it mixes without creating a large bubble at the top where it can make noise. Just small details that Rex had worked out over his testing and use. When I make changes to a plan, I have to accept any trouble that I create.
Kind of seems wrong to call something a Cadillac if we swap in a VW engine?
As far as the connection. Has anyone heard of one coming apart? It seems like it's as secure as a hose pushed over a plastic barbed fitting.