i agree with john. i wish i had taken a pic of tht before assembling my tank, but you have to have a length of some type of hard line/tube going about 2/3 into back of tank, then a shorter tygon to clunk, to keep the clunk near the rear, or it will end up stuck in the front of tank sooner or later. then down comes birdie, due to a flame out, way before your time limit on flt. (or so i've been told)