As a precaution to someone reading this, just because Quantum didn't have an issue leaving his waterfall going despite ice--I can't recount how many times I've heard of folks not turning off their waterfall and water freezing in such a way that water is able to trickle out and exit the pond following the ice trail.
I do not recommend leaving your waterfall on in zones where you get water freezing or ice. Waterfalls are notorious spots for exiting water during the summer...never mind during a winter freeze. And if something does go wrong, trying to correct a problem like missing water volume in the middle of winter can be devasting to a pond.
Don't take the chance--shut off your falls if your water has any potential of freezing.
I do not recommend leaving your waterfall on in zones where you get water freezing or ice. Waterfalls are notorious spots for exiting water during the summer...never mind during a winter freeze. And if something does go wrong, trying to correct a problem like missing water volume in the middle of winter can be devasting to a pond.
Don't take the chance--shut off your falls if your water has any potential of freezing.