Winter pond cover

[marco]

This winter I intend to heat my pond. I have already install an electrical heater and had experimented last spring. It works really well.
To spare some energy I have to cover the pond so I'm wondering what system is the best. Last spring I had problems with a floating cover because I had not enough air exange, so I would like to find a better solution.

The temperature can reach the - 20 C° during a few month and the snow doesn't alow me to use a flat frame over the pond.
My pond is about 4 by 3 meters and 1.5 meter deep.

What material would you use ? polycarbonate, polystirene and polycarbonate, sandwich of wood and polystirene ? others ?
I would like to profit of your experience on this problem, picture will help me too.
Thanks
Marco

[dick benbow]

here's what I'd suggest based on the following experiences

In my progression as a koi keeper, I soon focused on controling temperatures
for my outside pond. The water would get down in the thirties and was really hard on the residents. We also get episodes of snow so I built elaborate plastic and wood framing. which didn't vent properly was ugly and not always snow load proof. I laid 4 x 8 foot 2 inch thick styrofoam sheets on the pond and that kinda worked. I bought a swimming pool cover (bubble wrap ) to fit edge to edge and that turned out to be a nightmare. How my first asagi from hosokai and the first babies from diamond mask (sakai hiroshima) got out on top of it and died I'll never know.

So I gave up, built a fish house with an inside pond and heater and brought everything inside.
here's my suggestion tho in your case: get some kind of pellets you could float for insulation. It would still allow gas exchange and if a fish jumped out it would crash thru back to the pond! I would anticipate it would be a chore of clean up in the spring.

[marco]

Hi Dick,
I found these balls on koï shop in germany, are you speacking of this kind of material?

[Dan Blatt]

2 x2 frames with polycarbonate panels......works great.

[Tom C]

Dan is your cover vented in some way?

Tom

[Dan Blatt]

Tom...correct. Along the side near the Japanese red railing above the pond I added a spacer piece of 1 x 2 on the bottom where it sits on the pond edge. This provides slope for rain to run off the opposite side, and additional venting. However the polycarbonate sheets are waffled and provide plently of venting also.
Keeps my temperature swings to a minimum in winter...less than 2 degrees in a 24 hr period when really cold for extended periods, and less than 1 degree in 24 hrs, the rest of winter. Koi are always active under the covers, although slower obviously. No stressing and sitting on bottom from cold temps.

[Jules]

I wil be on my 3rd winter with the balls pictured below. I purchased them from the Early Learning Centre buy 2 get 3rd free. They allow plenty of gaseous exchange and if the koi jump they fall straight back through. They do not fight over the food either as it is spread evenly between the tiny gaps.

Not every ones taste but saves a lot on the gas bill.

Jules

[MikeM]

LOL !! ... I've never before seen such an approach to covering a pond. My first thought was how they would block the skimmers.... goes to show that I do not "think winter".

[dick benbow]

you can fly in some winter's day and we'll put you up mike. I'd hate to think of you being deprived and all.

[Jules]

The skimmer has a grid similar to the one below. This keeps the koi and the balls out but still takes the surface waste off.


Jules