Just a follow up update. Yesterday for the first time, there was a thin section of ice on the top of the pool in the middle. Probably about 8 feet in diameter. It melted by the end of the day yesterday. However, this morning, I noticed the pool water didn't look like it was moving. I went out, pump was running and water was circulating. But the skimmer was full of small thin chunks of ice and there was a sheet of ice on about half of the water surface (17F outside). I reached in, and pulled out the ice chunks and immediately could see and hear the water moving faster. Regardless, there were no signs that the pump had stopped or slowed down to cause any issues. I'll keep a close eye on it today.