FnC,

Remember the only time water should be running out your syphon pipe is when NEW water is entering your system (IE rain or snow melt) and that water should be better quality than the water at the bottom of your pond. What should happen is that as the bottom water is syphoned away, newer water replaces it from the top down. The only thing I could see happening is that your pond might get a little colder towards the botton temporarily but I'll always take better quality water for my pond any time.

Any thoughts from the experts?

Brian

The one thing is the one thing
A dry fly catches no fish
Try not to be THAT 10%