I keep a very good quality pump running 24/7 for 4 plus months and significant time on shoulder seasons to keep a 1/2 acre pond that is 20' deep clean for swimming. It runs two diffusers off two lines with something like a 100' run from the pumphouse. Cheaper than replacing all the time. Be careful of false economy of a cheap pump not designed for the job and assuming you only have to run it a few hours a day. We'd like to add a windmill for for the view and as supplimental pump, but it wouldn't output anything near the same volume for the same duration.
We add no chemicals to the pond and try to maintain a healthy system. Lots of frogs!