what pump do you use to start a syphon or do a water change?

[viodea]

Do you use a pump to start syphon? How do you do it? What pump?

Do you use gravity feed or pump for water change? I can gravity feed to my sump but not to the display tank. I'm not sure my gravity feed can keep up the pace with my return pump though. Which means I have to start and stop my return pumps a few times before it's finished. Is it a bad thing to start/stop so quick so many times?

thanks