I finally figured it out, thanks to your advice, snrub. I put a 90 degree fitting on the bottom end, and it has been gushing like an artesian well ever since. Unfortunately all I could afford was 2" PVC, so it is slow going. When you figure in the rain, well, you get the picture. Now that I have the system figured out (on attempt 11 or 12), I just need about 7 rainless days to finally get it drained.
I drained my 1 1/4ish acre pond last year with a 2" pvc line, the drop rate will speed up as the pond gets smaller as long as you have plenty of drop on the back side. I think it took a little over 2 weeks to get mine lowered down the first time and then there were several restarts after big rains that came thru last fall. I ended up dropping mine over 10 feet using nothing but a siphon.
