Window for outdoor pond that freezes

[MrMudkip]

Not about monster fish but figured this would be the best place to ask.

What considerations are needed for window ponds outdoors in a climate that freezes during the winter?

Would I be correct in thinking glass is at risk of cracking so acrylic is the way to go? Or is glass fine?

Usually in my climate the ice we get range from a slight film of ice to 4inch/10cm thick. Obviously I can make it so the top of the window is lower then the surface freeze point but are there other other things I should keep in mind, like if it rains and then the water on the outside of the window freeze's.

We do get melt and refreeze points at times during our winter but it's worth noting that if it reaches the point we're we have more then a few mm of ice in the melting stages it usually doesn't fully melt before refreezing.

When we freeze this usually last 2-3 weeks.

I plan on making concrete ponds btw unless if someone has a better option, I'm assuming no to wooden as I can imagine the wood flexing with changes into temp.

Thanks

If anyone is wondering what's it's for in the future I plan on moving my groups of turtles, Axolotls & Sharp Ribbed newts into window ponds once I'm living in a place I have the mortgage on.

I've kept these guys outdoors year round in big tubs for the past 5yr and when I move I'd like to move them into ponds with windows to allow for viewing them side on as well as from the top.

Obviously they are in separate tubs from eachother and will be in separate window ponds!

Thanks again

 

[Fishman Dave]

Not been something I have attempted. My pond that freezes (outdoor one) has no window but I know a number that have glass windows but I am fairly confident they are kept from freezing by moving water, either by pump or airstone. Personally I would want to go perspex/acrylic just because I wouldn’t want a glass pond shattering and I would expect them to be more giving. Obviously if the viewing pane is lower than the top you remove a lot of the expansion issues, but, it gets harder still to seal and you miss being able to view them at the surface.

 

[jjohnwm]

Disclaimer - I'm not recommending this, just describing an incident that occurred to me.

I had a round black stock tank "pond" at our cottage in Ontario. We considered it to be Up North, although it's much further south than I now live year round. Even so, ice was at least 30 inches thick most winters. One year when we closed up the cottage for winter, I forgot to drain and turn over the stock tank; by the time I remembered we were several hours south and not about to turn back. As we often did, we went up for a few days of winter fun between Christmas and New Years. I expected to find the tank split wide open.

It was fine! The inverted conelike shape of the thing allowed the water to push the frozen top ice higher and higher as it froze beneath, so the upper surface of the ice was flat and perfect, but about 2 inches above the top edge of the stock tank, which was undamaged. That early in the winter there may have still been some liquid water near the bottom, but I doubt it. In any case, the thing was frozen solidly to the ground, so I just left it alone.

The next spring everything thawed and the stock tank was completely undamaged, and continued on in use for many more years afterwards.

I'm planning on experimenting with installing windows into some of my current stock tanks. If the job isn't too much of a PITA, I will likely let one sit full of water throughout the winter to see how it fares.