I too have considered whether this would work. I have a biorb syphon which has an inline starter bulb and I have wondered if by adding a length of hose to the end it would then syphon straight into my kitchen sink.
I also have one of those push on tap shower spray things and I've also wondered if I can put water back to the tank via a long length of pipe.
One day I'll get a length of pipe and try out my theory cos lugging 7 buckets a week is slowly becoming tedious