gene wrote:

What zone are you in? If you are above Zone 6, you have to anticipate
freeze problems. I am in Zone 5, and my 4X6 3.5 deep 3/4 inch plywood
pond has 3.5 inches of foam board insulation betwen the inner and
outer walls, and I put a 100 watt aquarium heater in the water in the
winter and cover it with a two inch thick foam insulation board. It
never goes under 40 degrees, even when it's below zero outside. I also
have foam board under the liner, but I don't know if that helps or
hurts-- maybe the earth heat would keep the pond warmer.

Intuitively, I would say it hurts. But I don't want to build two identical
ponds (save for foam underneath) to find out :-)

My pond is not on my deck, it's next to my deck, so I can look down
into the pond from the deck. Or jump in if the spirit moves me.

Exactly what mine's going to be.
--
derek