From this site I find that the outer diameter of a 1.5in PVC is almost 2in (1.90in). Can I just slip a 2inch backwash hose around a 1.5 pipe with a clamp on it and call it a day? I'm about to glue a barbed hose slip, using a coupler, to a 1.5in PVC backwash pipe, which is way more work then just a hose clamp.