Stick your hand in front of the output...
What kind of media do you have in that filter?it could be that you put too much or compacted it,do you use any sponge or anything like it but less porous?
Also check for kinked hoses. But, as gmccreedy so elegantly puts it, forget the suction; how's the output look?
Connection are good, no kinks and silent as could be. Maybe I was just expecting more than I should have seeing as I don't have much expirence using canister filters.It does sound like something isn't right. Double check all your connections and be sure they're opened all the way.
Is it noisy?
It seems a little better. A shook up the filter and maybe that made the filter media even out a bit. The flow seems to be a little stronger.They do seem sluggish compared to other filter types, but you should get a decent spray from the output. I guess it's hard to tell without seeing it if it's really slow or not. If the holes are horizontal, do you at least get a few inches of horizontal squirt? (technical terms, ya know!)