Well, tonight I'm pretty sure both skimmers were struggling to work as ice had formed in front of them probably deeper than the opening, which is only 4". So, I shut off those pumps, which turned off the bog in the koi pond (no problem) and stream going to the goldfish pond (again, no problem). The koi pond has the air bubbler doing it's job, and the goldfish pond has water bubbler, with heater running in the center to help it out, and the big pump is still pushing water through the large bog, I could see it still flowing. I have no idea how Colleen keeps water running in her ponds in her cold! I sure don't have the knack at it ... yet! At this point, I'm pretty sure I'll shut things down next winter, just keep a hole open once the water freezes over most of the pond, and not worry about the pumps. All pumps are at least 20" or more below the surface, so no worries of them freezing solid. Guess I'll find out if the skimmer boxes get damaged, but I can't imagine they won't hold up to the ice, since some people build them into the liner wall, so no way they would be brought inside for the winter. I just wanted to see if I could keep my water running, but not much luck. Maybe the water will stay somewhat warmer without as much water movement. We shall see ... but I don't have a bottom thermometer, so have no way to know at this point. That's on my "to buy" list for this summer.
Temps today went from I think 9 this morning to about 20 maybe, and now dropping again. Supposed to be warmer the next few days, back into the 30's, so it's all good.
Stupid horses played with the floating heater and got it on top of the board I had across the top of the water trough to keep them from messing with the heater. So, it was not heating the water and was frozen solid the top probably 10" or so. Good thing the water level was low, just added water and checked to make sure the heater was still working, and they are back in service. Just will have to check more often for them messing around with it.