Hi I have been setting up a new 60 ltr Jewel aquarium that came with a bioflow one internal filter. The filter is installed and pumping water ok but the small tube at the top of the outflo which is supposed to draw air is not doing so,the pump is actuall pushing a small amount of water back up the tube. Ive tried adjusting and blowing down the tube to clear it but nothing works.Wonder if anyone has a solution tothis problem ....Thanks