George wrote:
If these are large submersibles, you should be aware that they can heat
up significantly at such high head loads. This could cause problems
with maintaining a proper tank temperature.

Good point. I think one of these two will work. I'm leaning towards
the smaller one.

http://tinyurl.com/ygagh8
http://tinyurl.com/ycx8fw

They are both external, so air cooled.

--Kurt