If you want efficiency let the can work on its own. Trying to connect it to the R-UG is a bit redundant, and may be counter productive.
For reverse UG, all you need do is keep the power head as is on the UG tube, it alone will send enough water threw the gravel to aerate the substrate.
Using the venturi to suck air, reduces efficiency and strength of flow slightly, (up to 20%).
I use ventures regularly to add aeration, they work best when not having to push against head pressure.

For reverse UG, all you need do is keep the power head as is on the UG tube, it alone will send enough water threw the gravel to aerate the substrate.
Using the venturi to suck air, reduces efficiency and strength of flow slightly, (up to 20%).
I use ventures regularly to add aeration, they work best when not having to push against head pressure.
