frost lines and shallow ponds

Call a builder and ask how deep a foundation has to be (they have to be
built below the frost line). DK
"Doug Swetland" wrote in message
...
O3raledale wrote:

Hello all,
How does one find out what the frost line is in their area of the
country? I
live in Philadelphia, PA. and my pond is only about 18" deep. Will my
goldies
be safe in there over the winter with just a couple of air stones going?
Can I
leave my filter waterfalls/ stream going until it freezes to the point
of
spilling out and then turn off the pump and start the air bubbler then?
Please
let me know your thoughts on this matter.
Thank you all,
-Pat


Pat,

You could check with the state department of natural resources (if PA
has one) or the county agricultural agent. They might know something
about average ice depths on ponds.

The frost line in Minnesota is nearly four feet and my partially above
ground pond (10 feet by 15 feet by 3 feet) gets about one foot of ice in
an average year. The real variables are the air temperature and the
amount of snow cover. I usually have a couple of feet of snow on my
pond and that is a great insulator. By March it is hard to tell where
the ice stops and the snow starts.

I use a 1200 watt de-icer to keep a one foot hole (looks like a cave)
open in the ice for gas exchange. It turns on at 32 degrees and off at
34 degrees and uses about the same amount of electricity as my 700 watt
4000 gph pump. The pump is on a timer and only runs 16 hours a day June
through October.

This setup has worked well for six winters. Except for the year the
de-icer sank to the bottom and the hole froze solid. I didn't notice
that for a couple of weeks and all the fish died. I now prop it up with
a column of bricks.

The problem with me bringing the fish indoors is they have to be out by
October and don't get back in until June. What's the point in having
fish in the pond for only four months?

With only 18 inches you don't have much room for error if you get six
inches of ice. The volume of water and number of fish are also
important variables.

I'd give it a shot with the air bubbler and see what happens. If it
doesn't keep a hole open be ready to add a de-icer. However, don't keep
the falls/stream going until it freezes unless you have an automatic
level switch. Otherwise it will freeze some night at 2:00 am and you'll
wake up with an ice skating rink in the back yard, a burnt out pump and
frozen fish for breakfast.

dss