Hello I am in southern Ontario as well with a preform 220 gal pond I built a
cover for it and have a floating heater I purchased from TSC a few years
back but the heater I have can be difficult to find they only carried this
type for a short time under $ 40.00 and cost to run with the cover over it
is low , as the snow also insulates it this year I have my pump running as
well with a modified piping to keep the water moving . I checked them this
past weekend every one survived has there was some nights I was wondering
"Joel" wrote in message
4...
"Gale Pearce" wrote in
:


We had a few cold days here in the Toronto. Canada area a week or so
ago
and despite my best efforts I could not keep a hole open on my covered
pond. last week when it warmed up and went out and cut a hole in the
ice and shined a flashlight into the deep area and saw one of my large
14" koi dead on the bottom.

I had an airline running, but any moisture in the airline iced up and
blocked the air which is when my hole froze over.

Hi Joel - I am 35 miles east of Windsor and was having the same
weather as you. My airstone hole was freezing over like yours on the
coldest days and nights and I had to constantly keep opening the hole
when that happened with either a tea kettle or a steel rod - if you
let the "ice dome" freeze over solid it will start to thicken and be
next to impossible to open - that happened to me 2 yrs ago and I had
to use a 1500 watt heater that I sat on the ice and let it melt it's
way through to open the pond back up
I also have my airpump 3' off the ground (on my waterfall "hill")
and the
airline runs on a constant slope downwards with no low hanging loops
for moisture to collect in during thaw/freeze temp cycles, but we
haven't had any above freezing temps around here - have you? If not, I
would suspect the hole froze over solid enough to stop the airflow,
rather than the line freezing up
If you aren't able to check the air hole daily in the really cold
temps,
maybe you will need to use a 1200 or 1500 watt heater on a timer for
a couple hours a day with your airstone
I have been using an air pump for 10 yrs now with the airstone no
deeper
than 3" and it has worked fine for me even in the coldest winters,
except when I got lazy about keeping the hole open a couple yrs ago,
although T.O. has a bit cooler temps, I believe
It sounds like lack of oxygen, or rise in toxic gases as the
largest fish
are the first to suffer in those cases
Sorry to hear about your losses
Gale :~)




Thats a good idea about having the airline run downhill to keep moisture
going down and out.
My pond is small, 5 x 4 and 36" at the deep end, the ice is only 2" thick
and the airline was keeping a hole open, but the line froze up like I
said, I think next year Im goin gto try something different, put PVC pipe
from the pond to where I keep the air pump which is under my deck 3 feet
away, maybe as long as no snow or ice builds up on the airline, less
mositure will freeze up on it.

it is above 0C now, and I did the same thing, a poured hot water over the
airline to clear it up.
I was checking the pond once a week, so the last time I checked it, it
was fine, but during a week of cold unseasoned weather, everything went
bad.

I did try and get to the back earlier, but the gate was snowed in, I
couldnt get to the deck from the sliding door as it was snow in, the only
option was to climb the fense and that day when I was tring, it was -40C
give or take.

Everyear is a lesson learned.

My first year I had the pond, I didnt cover it up and I didnt have any
fish inside as it was too late in the season to stock it, so I used the
pond as a trial run over the winter, that year we also had -40C cold
snaps and by spring when the snow was gone, I measured the ice to be 30"
thick, good thing there were no fish that year.

I looked into getting a pond heater, but I wasnt prepared to spend
$200.00, I'll just have to check more ofter withthe airline as it seem to
work when its working.

Joel.