This Fluval 304 I have would not start/restart to save the world. Is there some kind of procedure I should go through other than the one in the manual? I prime it, turn it on, nothing happens (most of the time). The only time I started it was when it was on and I sucked through the "out" pipe till water started flowing out. This seems to nolonger work anymore. It's a used filter, not brand new... Thanks for the help in advance.