I had an issue with the pond last night, it got down to 14 degrees and where the water comes out if the filters it plugged/froze up and blocked the water from getting out of the filters, the filters over flowed onto the ground, but the in-feed to the pump is near the surface, so the pump went dry, that way it don't pump all the water out of the pond, I lost 4/5 inches of water, so I broke the ice layer up on half the pond to raise the water level in the pond so the in-feed would be under water again, I don't want to put tap water with chlorine in the pond right now and stress the fish.
The ice layer is around 3 or more inches thick, the air between the layer of ice and the water is how much water I lost.

It's supposed to rain next week, that will re-fill the pond if it rains hard enough.
I put a fish tank heater in the outlet tube, I am hoping that will keep it from freezing up tonight, otherwise I might have to turn off the pump when I go to bed tonight.
“The difference between genius and stupidly is that genius has its limits” Albert Einstein