Tom,

Noticed you are planning another pond. If you are interested, a discussion on stocking strategies and uses in a multiple pond situation might be of benefit to you. With multiple ponds, you have the option to do some things that a single large pond can not do. Just make a post on that topic if you would like to discuss, and I will throw in my 2 cents worth.
A strategy which views the set of multiple ponds as a system, I believe is needed to make full use of those options.