Unfortunately the deep freeze this week was too much to keep the pump going. The pond had frozen over a few weeks ago but the water was flowing fine, the stream and waterfalls were going. But this week with temps overnight below zero was too much. The pump sounded like it was struggling yesterday so I shut it down, the skimmer had started to freeze up so I think the water flow had slowed down. I dont think it will be thawing out anytime soon, temps overnight for the next week will probably be in the teens. The air line is still going and I will open up more holes in the ice over the weekend. I was spoiled with my first winter last year, it was warm and the pond only had a couple of days of being frozen.
I know you can take a big pot of hot water and hold it on the ice and let a hole open up but then I have heard after doing that you can place a rubber ball filled w/air and place it on the hole and it will allow the hole to stay open.
Found this info online and I've never had the need to try it so don't know if it really works or not:
Why The Tennis Ball Trick Works
A trick that has been used for centuries involves floating a rubber ball, ping pong ball, tennis ball or inflatable ball onto the water surface, depending on the size of the pond and leaving it, checking each day as the temperature drops.
You can also use a bottle filled with a saltwater solution that floats on the water.
The reason this works is that when the ball bobs and floats on the water, it creates little waves and motions in the water that stop ice from forming, and it will accentuate any movement of the water or anything underwater, helping to keep ice from developing.
The size of the ball you need depends on the size of the pond, with most garden ponds needing a tennis ball, and any larger body of water needing a football or larger-sized ball to be effective.
This, along with careful maintenance of air pumps and other pond tools can keep your pond life safe this winter.