Well I just got caught up on all 23 pages of this thread. I must say it is quite a pond. I have thought about building something similar but it would have to be indoors, because it gets well below freezing here for about 5 months out of the year.
Keep up the good work, and the pictures.
You might like to look into underwater camera cases. A waterproof case for your camera would come in handy. They make cheap ones that look like a heavy duty sandwich bag, with a glass lense attached to part of it. I have one for a Hawaii trip last year, and it worked great in my fish tank also. Of course in my tiny tank there wasn't as much to see as there would be in yours!