Too big is rarely an issue, whereas too small is always an issue. What size pump to buy depends on what size pond (in gallons) you own, and what you want to do with it. If you have a 1000 gallon pond, you want at least a 500-1000 gallon per hour pump. If you plan to operate several items, such as a filter, fountain, and waterfall, you will need a larger pump. Flow rate depends on how deep the pond is, how far away the filter and/or waterfall are positioned from the pump, etc. If you are trying to operate a filter, then look in the filter specifications to see what size pump is recommended. For waterfalls, you need 100 gph for 1" of weir at the very top of the falls.
Date published: 2017-06-05