We suggest the use of aquarium silicone as this will give a semi permanent bond. Apply the silicone on the stubs on top of the unit and push the elbows on carefully, leave for 24 hours before running water through the unit.

Using silicone will form a semi perminant bond. This will still allow the elbows to be removed from the unit in the future if needed.

Aquarium suitable PVC solvent weld can also be used, but this will be perminant. If the elbows need to be repositioned or replaced the entire lid assembly would have to be replaced.