Cecil, yes 1/3 hp can be a lot but I have seen cfm's as low as 1.5 with them.Most 1/3 hp rotary vanes and pistons are 4-5 cfm today.The Gast 0523 1/4 hp has 4.2 cfm open flow so these are powerful little pumps. NE Mason could probably get by with a small linear pump with the raised diffuser.The problem with the temp timers is you could go days in the summer without aeration and in a 1/4 acre pond run low on DO quickly.Perhaps a combination of timer, raised diffuser, (DO meter would be great also) Also with a 1/4 acre pond any type of aeration is going to warm the entire water column to some degree.Small ponds and trout are always a challange in the warm months.At times I wonder if all trout ponds are meant for trout year in and year out.
