John,

Don't know about DIY heaters, but there are
companies that supply heaters to the Aquaculture
community and they usually start out about 1,500
watts and go up from that point.

Tom L.L.
====================

"John Hines" wrote in message
...
"Madd Hatter"
wrote:

I was wondering if anyone has any ideas on
making a heater for a 700-750
gallon in ground pond, to keep it at about 75
deg in the summer months? I am
in the Toronto area, and from what i've
gathered so far, I shouldbe looking
at 65 to 69 degrees low during the summer here.
I want to make it as stable
as possible.

You need a heater of some kind, and an
electronic control to regulate
it.

Heaters are simple resistive electronic
circuits, so you could look for
a proportional heater control circuit.

A really honking big aquarium heater or two may
do it as well. I'm
thinking more about the in-line pipe heaters
than in-tank ones.