Abstract: The present invention comprises apparatus for initiating a fluid flow within a siphon tube from an aquarium to its associated filter tank. The novel apparatus comprises the addition of a vacuum duct with an upturned fluid trap to an otherwise conventional siphon tube; the detachable attachment of a siphon bulb to the trap outlet of the vacuum duct while both the aquarium and filter tank are full, with the filter tank pump being in an 37 off" condition; the squeezing of the siphon bulb in order to exhaust air from said bulb and ultimately out through the aquarium tank. The bulb is then released, thereby creating a pressure differential within the siphon tube which will cause the air within said tube to be drawn into the bulb. The removal of the trapped air within the siphon tube, and from the vacuum duct and its trap, will cause fluid to fill the siphon tube, and vacuum duct.