Zep the lines are at about 4 feet from water. It's 55 lb monofilament, because of the strenght and primarily because they don't have to easily see it, but get scared by suddenly finding/hitting it.
My pond is 1 acre and is rectangular shaped.
I planted 4 rebars along each short side and pulled the lines crossing them in the middle two by two. Then added 2 rebars in the middle of each long side and pulled other short lines under the long ones just to help support them in the middle (I never imagined how much 150 yards of 55lb monofilament could weigh...).
