Our pool has a second pump used for running the rock waterfall. It has its own intake inside the pool, so I figured it might be useful for this purpose. We were getting tons of leaves in the cleaner vacuum line, and this ultimately led to some pretty nasty clogs. I couldn't get them out using a Drain King (I actually ruined two of these in the process) and needed another approach. So, I ended up running the plumbing from the waterfall pump via a couple of ball valves to the vacuum line. By doing so and turning off the vacuum line's Jandy 3-way valve, turning on the auxilliary pump would run the water in reverse through the vacuum line. My rationale was that pumps are much better at pushing water than they are at pulling it. After running this for about 5 minutes, a big ball of leaves blew out into the pool out of the vacuum line, and after this, the vacuum line worked great.
This actually turns out to be a rather useful tool since sometimes the line gets filled with air (esp. if the vacuum hose gets disconnected from the leaf basket and starts to suck air). I just run the reverse flow circuit for a couple of minutes to purge the air and the system runs great. BTW, I had a leaf basket in line with the cleaner, but it was very poorly designed and allowed leaves to pass. My large haward leaf canister does a great job now and I've not had a single clog since then.