Hi Brian (@auroracrystals),
Seems like you should be able to just grab a length of Pope 13mm Vinyl Tubing and then use a couple of Kinetic 6-16mm 316 Stainless Steel Hose Clamps to lock it onto the outlet on the pump and the hose in the fountain.
The diameters are close enough in size that you should be able to slip the tubing over the pump, which uses a 12mm hose, and into the 15mm hose. With the clamps, they should stay where they are supposed to.
Hopefully, that is the last step, and your next update will be some photos of your now operational water feature.
Jacob
