I've developed a small (pin-hole) leak near the bottom of the tank of my trusty Gardiner backpack. Having a van mount I only use it 2 or 3 times a week in order to clean terrace backs but I need it to be totally leak free so I don't leave drips inside the customer's house.
Any ideas on how to patch this up? I don't really want to fork out for a new backpack if I can help it.