Nick,

In looking at the picture and description of your reactor, I think I have it figured out. If it works well, it should be able to supply your 180L with enough CO2.

You see that nipple at the top that has the little tube attached to it that extends down through and almost to the bottom of the reactor? That is where your CO2 feeds in.

Now is where it gets a little tricky for me. I think that the nipple that extends out sideways is where the pump will pump water into your reactor. The other knob at the top I believe is some sort of adjustment.

Here is what is supposed to happen: water swirls from the top of your reactor and out of the bottom as the pump pumps water into it. While this is happens, CO2 is coming out of the bottom of the little tube and will actually rise up against the current. While the CO2 bubble is rising, it gets swished around and will dissolve.

It is possible that the pump is supposed to pump into the other nipple at the top and the water gets redirected into the swirling motion, but I doubt this. At least you know what is supposed to happen while the reactor is running, so you'll be able to figure it out yourself.

By the way, in the Articles forum, there are some descriptions on how to make your own DIY reactors (internal or external), in case this one does not work out for you.

Read up on drop checkers too ... it's the only good way to really know if you are getting the right amount of CO2. There is a post on Drop Checkers in the Articles forum also.

And, yes, a reactor like this will always be better than a glass diffuser.