Newbie here - 100 glalon build.

[HTH]

It shouldn't if I had a heater/de-icer, or am I missing something?

As I said this is more of an outdoor aquarium then a pond. To keep it functioning outside in the winter you will need to wrap it in foam (like a big ice chest, and use aquarium heaters with good temperature regulation. A deicer may cook the fish.

 

[herzausstahl]

If its only a 100 gallons I wouldn't expect that you would have many fish in it. Personally, I would build it, and leave it fish free for your first winter to get a handle on what it would do, and if it seems like the de-icer is over heating the water, throw a thermometer in it and see what the temps are at. With that I don't think my concern would be it freezing solid, but a fluctuating temperature in the water when the de-icer kicks in. What USDA zone are you in? That would probably help people figure out the freezing possibilities.