IMO you want to run the aerator enough so the difference between bottom and top temperature is 5F or less. When temp is 5For less there is usually adequate DO on the bottom. Since your pond has only 18" secchi disk readings the DO will be consumed rather rapidly at the bottom and in all the water deeper than 4ft, thus mixing to achieve the 5F variation will help maintain higher DO in the deep water and at the bottom. Once you achieve the 5F temp range it should not take a lot of mixing per day to maintain it; possibly 10-16 hrs/day?. Experiment and report back.
Were you measuring the temperature at the deepest location or at the adjacent depth of the diffuser? Is the deepest water in the 'belly' the same temp as that at the diffuser depth?
Last edited by Bill Cody; 06/07/12 08:19 PM.
