It Originally was a galvanized pipe, I heard they had issues with that and replaced it with a double wall plastic pipe which they had a 90 deg turned up pipe in the pond, so it used to be bigger and 3-4 feet deeper. But they built the pond about the same time they built the house in late 60's. Not sure who designed the pond.
From other things I was looking at, I'm thinking I want the water to hit the wheel at about the 10 o'clock position. Any input on that? And how much will higher vs lower effect the efficiency? Will 2' fall be better than a 1' fall?
