If your pond is 25 ft deep make sure if the diffuser is in the bottom of the belly the pump has at least a 15psi or 30 psi model is better which provides a little psi 'buffer' for piping, distance,and back pressure due to diffuser clogging.
If I had a pond is as big as 40 million gallons, I would do a stratification survey plotting DO, temperature, and depth contours. A good aquatic ecologist would then look at biochemical oxygen demand, water shed fertility, nutrient budgets & status, productivity and then be able to determine if a complete calculated turnover was needed, if aeration was even needed, and best how to manage this water body.
Last edited by Bill Cody; 02/11/13 10:20 AM.
