I set up my new pre-formed 175-gallon pond this past weekend. It's full of plants, and I plan to eventually add some comet goldfish and rosy red minnows. I need to add a filter with a fountain - just a simple splash. I'll get one of those box type filters (Beckett makes them) with the pump inside & some filter media, with the pipe coming up and a spray feature on top. (My other two small pre-formed ponds, which came with the house, have this sort of filter.)

What size/strength (gallons per hour) pump should I get for the filter box? Is there a rule of thumb; the water should circulate once an hour? Twice? ... The pond is 175 gallons, and I'll want it's outflow to power a small splashy fountain.

Thanks!

Leslie