PVC connections attach to pond liners with two adhesives, a primer and a glue. Once attached with this incredibly strong adhesive, the materials are more likely to break or crack before the bond joining them will separate. More time will be spent draining the pond and preparing the connections than it will take for the adhesive to bind them.
Drain the pond and air-dry all exposed parts to be bonded.
Test-fit the PVC connectors to the pool lining before using any glue to familiarize yourself with the way the parts fit together. The glue dries quickly to a permanent bond, so there is little room for error.
Apply primer to one of the PVC connections and let dry. Primer cleans the joint and provides a better bonding suface than PVC alone.
Apply a thin layer of glue to one of the PVC pieces being connected.
Connect the PVC to the pool liner, orienting the parts for correct alignment, and hold tightly for one minute.
Allow one hour of curing time for the glue to set and dry before adding water.