Bill, do you think with the extension down 15 ft will get more DO at that depth. There is only about three trees on one end of the pond, I get plenty of wind action on the water, so much so that I just had the whole pond lined with 6 and 2 inch rock, wow, have you all priced rock lately. Ripples were eroding a shelf on my dam and I wanted to make sure if someone slipped in they would have something to grab on to get out, especially in the winter