i cant see the brand, the unit is in the sump. No paper work from previous owner. The is a red handles valve on top, when i turn valve an increase the water flow. You can see water level creep up into the first chamber. I originally read up on this unit, the valve should be adjusted so the water level
is high enough that you cant see it through the first chamber. The bubbles then rise into the second chamber and out a tube into a bottle.
The water does vary in the sump, but it should not effect the flow, the intake tube is resting on the bottom of the sump and always covered by water.