Like Scott said above, you need around a 1.2-2 volume turnover per day, but that 1.2 is bare minimum. I like 3-5 times per day on turnover for the best oxygenation and destratification. I love the performance of Airmax, and would suggest a PS20, minimum, for a more angled pond. Improperly installing, or an undersized aertion syastem is often worse than no aeration at all....done wrong, or undersized, you effectively. create a phosphorus pump
