git1fiddle,
I have been running my system 24/7 spring to fall, but am now in the process of building a controller that will run it based on the temps in my water column. You are right, power usage is a killer. My 3/4hp pump runs about $90/month. There isn't much left to cut out of the budget. This past fall I first tested for Dissolved Oxygen with the pumps running, and since then with them off. There was no appreciable difference, (but that was late fall). The reason I haven't run it on a timer is that my four aerators are at 17', 9', 6' and 5' and it is difficult to get them all started and balanced on one pump. Once they are going they are just fine. Hopefully I can get my programming to work and save some $$ this year. Suspect with the 7pm-7am you are hoping for time-of-use on the meter. I may end up going that way too. Hopefully someone else has cycled their system and can give you some more info.
