So this is our first winter with ducks. And now that it will be 10 degrees for the next several days i got the heated pet bowl i heard so much about. I put the board and brick on top to keep the ducks from swimming it. Questions: Anyone keep this plugged in all night? If you do, does it melt easily in the morning by the morning? I was thinking just unplug at night, then put new warm water in the morning - hoping combination of warm water and heat will melt any left over ice. THOUGHTS???