Thanks Theo for the info. Now I need to think about the freezing aspect of the project. It doesn't get that cold every winter but there are times when the pond will get a thin layer of ice on it. I was thinking about using plastic, do you recommend using metal? Also I was going to use an elbow because I wanted to use a 45 degree entry into the pond. do they make a 45 degree T? I like the idea of being able to access the pipe through the T. Thanks again for any help.