I've been playing around with the HOB skimmer on my newly setup tank, which is cycled and moving along nicely. I got a Maxijet 1200 and did the DIY mod to get the venturi air on the inlet and it is working great, I think. I am getting a ton of micro bubbles going up the first chamber of the skimmer up towards the cup, ...these aren't supposed to be large bubbles, are they? Once I adjusted the height of the cup, I started getting some white skim into the cup within ten minutes. Not much accumulating, but at least soem movement up the tube into the cup. I just am not sure about the huge blast of micro bubble jet I am getting,or if it should to toned down a bit and have fewer larger bubbles.