sorry for the delay in a reply.
XP filters do have a tendancy to get air built up. On a new filter, the lack of slime coat on the inside of their ribbed hoses makes it easier for air to get trapped. It'll go away in time.
One tip I have for all XP filter owners, is burping the air from it. You'll find that you might get an inch of airspace at the top of the filter sometimes, especially us planted, CO2
If you see it, simply unplug the filter for a moment. Press down FIRMLY on the lid, and unlock the two front hinges. VERY lightly release pressure on the lid so the air can be pushed out from the lid seam from the water's force. It only takes a second or two at most. Then press down hard again and relock the latches. Plug the filter back in.
How far did you get the tubing on? I'd go for 1.5". its not a lot of pressure though so as long as the hosed can't be snagged by something or easily pulled on, they're not gonna fly off.