IMO your pond is large I would do at least 3 spots. Cause your probably only going to open an area about 20 ish feet in diameter maybe give or take. I'm not sure I don't do winter air so not sure on how big a hole you cam make.
I would think if you can power 3 duals effectively I would do 3 duals if I remember right your pond is long so I would do my best to put one in center and then go left and right as much as I can with the other 2 setups. I would think that would leave you nice 3 spots for them fusers to do their job.
The other thing that scares me about your situation is possible line freeze stuff like that. So having 3 spots would be good in case one ends up not working right. I hope it works for you that pond is awesome and your land their is very cool!!!!
RC
P.S. I am no expert when it comes to winter air though so lets see what others have to say.... I don't want to steer you in the wrong direction.
Last edited by RC51; 08/17/17 11:47 AM.
