Drain on recirculating skimmer/CO2 scrubber

[BriDroid]

I got this skimmer adapter and scrubber a while back. I’ve been running with the drain on my cup open. Should I close that drain and let it empty into the chamber on the skimmer? It has a float sensor for my Hydros installed, so I can shut the skimmer down if it gets full.

I’m just confused as to which drain I should use.

 

[Rocks reef]

Are you able to have the skimmer cup drain in to a different container?

 

[BriDroid]

Are you able to have the skimmer cup drain in to a different container?

That’s what I have been doing. I’m just wondering if I’m sucking in air through that hose when it’s not draining.

I’ve reached out to manufacturer to see how they intended this to be setup.