[MrBasse]

What was the reasoning behind the 90 degree air fittings? Why not just run tubing and eliminate a potential leak point?

The o-rings in those are really only good once or twice and then you are asking for a slow leak. If you do want to keep them, make sure that you insert your tubing all the way and then pull gently to seat the barbs into the tubing. And every time you remove the tubing you should cut the old end off to give new material for the barbs to bite into.