Pour a cup full of tank water into the outer box so the syphon tube is under water at both ends.Then insert a section of 1/4" airline tubing into the syphon tube till it is at the top of the turn.Then just quickly suck(with your mouth) the air out of the tube.Pull out the airline while plugging the end with your tounge,then start the pump.That should do it.If you have any Q's,,,,email me...GOOD LUCK.