Tom Barr designed another version of that reactor, which I used for awhile. It worked very well, but it also filled the tank with microscopic CO2 bubbles, which eventually irritated me. I quit using it for that reason. Another design is a very tiny in-tank filter, the Hagen Elite (I think that was it's name), which was used by having the powerhead portion suck the CO2 bubbles into its inlet, so the rotor chopped the bubbles up. That, too, worked very well for me, but also generated more microscopic CO2 bubbles in the water than I wanted. It's main advantage was its very small size. Still another design modifies the powerhead rotor by either shredding the paddles on it to make it a needle wheel or by melting lots of holes in the paddles to get a similar effect. All of these work by reducing the CO2 bubbles to extremely small ones, making them very efficient.