On Wed, 13 Sep 2006 17:41:53 -0500, Köi-Lö $##$$@$##$$.#$$ wrote:


"John Bachman" wrote in message
.. .

In cold weather the diaphragm
gets stiff and cannot generate the pressure needed to get air down 36
inches or so (that should be about 1.5 psi).
================
I was told NOT to put the bubbler near the bottom where the warmer water is
in winter. It goes nearer the top to keep an opening in the ice. It should
not be deep enough to be roiling and mixing the colder and warmer layers.

I have heard that too but do not buy it. Water is funny stuff. It is
most dense at 39 F. That means that as still water cools below 39F it
rises to the surface leaving warmer water at the bottom.

Now if you put your bubbler in the warmer, denser water at the bottom,
it will carry some of that warmth to the top producing a hole in the
ice.

I believe that putting the bubbler near the top will result in more
ice build up there than if it were at the bottom. As it is, during
real cold weather I have to break open the hole with a shovel or
something so I really do not plan on moving my bubbler to the top as
that would result in more frequent and denser ice-overs.

This system has worked well for me for three winters now so I do not
plan to change.

Your mileage may vary.

John