I think Aflac is referring to the Tube that goes down inside the middle of the reactor that supplies the CO2... That's why they said "Ridged Tubing"... Home Depot & Lowes carries them, even my LFS does too... I don't know where in Canada you'd find them, but, if you have a hoe improvement store around, they would probably have them there! I don't know what size to use either, so I can't help you out there. I would guess it should be able to have the CO2 line go over it snug. <~~???