This question is answered in part by whether you want a "trickle" or a roar. When you buy a fountain, you will usually find a recommended flow. For waterfalls, use this as a rule of thumb: for every inch of stream width or waterfall "sheet," you will need to deliver 100 gallons per hour at the height you're pumping. So if you are building a 12" wide waterfall that is three feet tall, you need to buy a pump that will be pumping 1200 gallons per hour at three feet of height.

For ponds, whenever possible, it is a good idea to recirculate the water once an hour, more often if possible. Thus, if your pond is 500 gallons, try to buy a pump that will recirculate water at a rate of 500 gallons per hour. For really large ponds, this is not necessary and is far too expensive.

For a nice waterfall effect, we usually advise about 4000 gallons per hour or more at the top of the waterfall. This creates enough volume for a wide, crashing spill. Adjust stones to soften the splash if desired.

Company Resource:    Household Heat Pump, Swimming Pool Heat Pump
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