My pond never has looked like the pictures you see clear and clean all the way to the bottom. My water is clear but because of gunk leaves and my water plant you don't see the bottom. So bottom line don't waste your time or money. I also agree with wanting to dip out the bottom of your pond and rocks would just make it very difficult.
I'll say it again - I would never put ROCKS (i.e., small boulders) in the bottom of the pond. That would make scooping difficult if not impossible and would trap gunk in between the rocks creating a potential problem. That, however, is a COMPLETELY different scenario than a GRAVEL bottom pond. A shallow layer of gravel adds to the biological processes taking place in the pond by giving bacteria surface area on which to colonize. It also, I believe, gives koi and goldfish an outlet for their natural rooting instinct. Our fish move gravel around out pond constantly. The gravel is so shallow that with one swipe of the foot you can expose the bottom liner.
I am not saying you HAVE to have gravel in your pond, but I do like to dispel the myth that gravel in and of itself is a problem in a pond when in fact it is actually a positive factor.