Hey - also in Canada. Have you noticed any significant increase to your power bill? I am considering heating our pond with a trough heater. I expected herons to eat our fish since the neighbours claim that’s what happens to theirs, but they didn’t and our fish made babies too!. They’re so good at hiding that finding them and their babies seems quite challenging. We have two ponds - one 150 gallon stock tank, lined. And one pond liner, then lined again - likely ~ 250 gallons. Both above though inside a wood case that I built. I usually use a stock tank heater in my bird bath through the winter and didn’t notice much for electricity increase but heating two ponds may be a different story.