How to choose a Pump

How to choose a PumpFor example, if your stream or waterfall spillway
Pumps are available in both submersible andwill be 10 inches wide, you will need a pump that
external (out-of-pond models). Reputable waterproduces an excess flow of 1000 GPH at your
garden suppliers have charts and otherwaterfall's height.
information available that can help you select theChoosing a pump that is too small will result in
best model and connecting equipment for yourpoor filtration and surface skimming, excessively
purposes. For the smaller pond, a submersiblelong filter cycles and in the case of a bigger pond,
pump is the most economical.poor action from the circulation jets. You must
Pumps are sized by gallons per hour (GPH) outputalso remember that as dirt is removed by the
at one foot of lift or height. Larger capacityfilter, the pressure goes up, increasing dynamic
pumps are rated by horsepower (hp).head and slowing flow rate. Therefore, you must
Manufacturers offer charts that break down theallow for that increase in pressure when choosing
power of each size pump according toa pump.
incremental heights of one foot. Some companiesChoosing a pump that is too large can result in
label pumps by GPH while others assign letter ordamage to the plumbing and equipment. It can
number designations that require cross-referencingalso result in cavitation, which can seriously
to charts.damage the pump itself. Cavitation is the
To determine the correct submersible pump forformation of bubbles in the water, very near the
your pond, you should determine your pond'simpeller, that occurs when the water is intensely
volume. It is recommended that you circulatevibrated. As the bubbles pop, shock waves are
your pond's water once at least every two hours.created within the pump that not only make noise
Hence, your pump should have GPH (gallons perbut also burst with enough force to damage the
hour) rating of at least half of your pond size. Forimpeller and other pump parts. Pressures caused
example, if you had a 1000 gallon pond, then youby cavitation have been calculated to be in the
will require a 500 GPH pump.range of 30,000 psi!
If you have many fish, or accessories such asAn oversized pump can also create excessive
fountains, waterfalls, or streams, you shouldflow, which can cause erosion of the system's
account for this to be getting a larger pumppiping. According to NSF and IAPMO standards,
(preferably one size larger). The general rule ofthe flow rate in 1 1/2-inch pipe should never
thumb is that you should double the pump'sexceed eight feet per second for copper and ten
capacity if you are planning to add fish.feet per second for PVC.
Calculating the proper pump for waterfalls is a bitSo when it comes time to buy a pump, the key
trickier, because waterfall pumps are rated byfactor should be performance rather than size.
both GPH and maximum waterfall height. ToDetermine the flow requirements of the system,
estimate your waterfall's height, you mustthen consult the pump curves provided by one or
measure the vertical height from the top of yourmore manufacturers to choose a pump that
pump to the top of your waterfall or stream. Inmeets your performance needs.
addition, you must add another foot of height orThat way, you'll be replacing the pump truly " the
lift for every ten feet of hosing you will be usingnumbers."
(this will allow for loss of volume from resistanceDiscover the best Pump Inforamtion site on the
within the hose). To calculate the required pumpWEB!
GPH, a general rule of thumb is that each inch ofSEO Solutions and one way link publicity services
width of the channel will require an extra 100 GPH.provided by LinkAcquire.