What is the best type or design to use? Most cost effective?
Here is link to a syphon system setup with a trash guard.
http://www.easywayplastics.com/page/page/1478349.htm
I am contemplating on installing one of these systems myself and have a concern about the discharge trap freezing in the winter anyone here have one of those systems in that environment. I want to have a bottom draw set up to move the water in the bottom of the pond or close to the bottom. Anyone have any other suggestions?

Dreaming of the pond!