My goldfish pond got completely iced over 3 days ago, bubbler pump quit, so the neighbor kids taking care of ponds unplugged everything, which is what I told them to do. Good thing is that I thawed out the area in front of skimmer and then got it and the bog pump going again, including the stream which runs off of skimmer. Today there was enough open water to pull the bubbler pump, and found that it was covered with mossy algae stuff. That pump has a filter sponge at the intake, in the "cage". Thought about taking the sponge out, but left it in to save the pump. While everything was thawed out (both ponds are 90% open at this point) I cleaned off the sponge filters on both skimmers, and got the waterfall running again.
I'm sooo ready for spring, too! Was 56 today, but tomorrow only getting up to 30's and then lower on Monday. This see-saw temp stuff is hard on everything, including animals with fur, and vegetation, and us! Teasing us thinking spring is around the corner and then BAM, winter is back. But, as you said, at least the days are getting longer again.