greg,i would like to purchase a aeration system from you for my 4 1/2 acre pond.what type should i get?pond has water from 3 feet to 6 1/2 average,although i do have a little water in in7-71/2 range.and about how much money to purchase system?thanks.p.s.feeder you sold me works great,nice not having to got out in the rain,feeder does not mind working in these conditions.