What size de-icer do I need for a 1000 gallon pond?
The K&H Thermo-Pond Deluxe 1500W. K&H's pond chart asks for 1500 watts on 750 to 1000 gallons, about 3,800 L at the top end, in zones 3 and 4. The chart starts at zone 3 and most of Alberta is zone 2, so this is the one to pick here. Pipestone Farm Supply carries it.
Sources: K&H Pet Products, Thermo-Pond Deluxe and zone chart