mag 18 isnt big enough for the monster skimmer?NEED HELP!!!

[Tarolisol]

The beggining of my injection chamber is level with the top of the reaction chamber. The only thing i see wrong is i cant get the bubbles to go from the injection tube(2.5") to the reaction chamber(6"). So if i shorten the reaction tube down to 3 feet you think and then shorted the injection toube to maybe 4 feet this should work better? Also it would seem my injection housing is filling with water quite quikly is this normal?