The
inlet pipe allows the unit to be primed for the initial filter startup
and if the filter needs to be re-primed after a major cleaning or tear
down and reset. Once primed, water from the aquarium will be drawn
through the intake strainer into the inlet pipe and out of the aquarium.
This water flows into the canister and should fill the canister to the
top. Just restart as normal. This is version two but it will also work
with the original accessories. This version includes the filler cap.