On Fri, 30 Sep 2005 22:44:01 -0500, Redshift0 redshift0#comcast.net wrote:

I'm worried about them
surviving our Massachusetts winter.
How big a heater do I need? Do I need a water circulator too? Would I be
better off buying an indoor tank?
Some stats: the pond is 40' x 15' and about 6000 gallons; the koi are 6" to
12"
---Steve

Air pump w/stone and stock tank heater on the standby when temps go too
low. Or, a small pump on shelf moving water at the surface. ~ jan