Water Pumps
With the variety of water pumps available  today, selecting the ideal model for your application can be tricky. The following are a few useful definitions, helpful hints to aid you in your decision:

       Centrifugal Pump: Medium- to moderate-pressure,  flooded-suction or
       self-priming pump. An impeller is used to "sling" water to the outside, pumping by
       centrifugal force.

       Check Valves: Installed on pump outlet to prevent  back siphoning when off.

       Flooded Suction: Water must enter pump by gravity.

       Foot Valve: Installed on a pump inlet to prevent  the loss of prime during
       non-operational periods.

       Freshwater Pumps: Freshwater pumps can be used  with salt water for brief
       periods and experience only minimal  corrosion. Rinse with fresh water after use.

       Head: The amount of pressure that a pump must work  against during operation.
       Total head equals feet of vertical lift  plus friction. The amount of head is an
       important value when  sizing a pump correctly. One psi equals 27 inches of water.

       Friction: The loss in pressure and volume that  occurs when liquids travel through
       pipes, fittings and other  restrictive elements of a piping system.

       GPM: U.S. gallons per minute.

       Pedestal Pump: A self-supporting pump mounted  above a long shaft with the
       motor above water and the intake below  the water level.

       Pressure Curves: Motor overload can occur if pumps  are operated below the
       lowest pressures depicted by the curves  shown in the pumps specifications. If your
       application does not  have sufficient head pressure to stay within the curve you
       should  throttle the outlet with a valve or other restriction. Use an amp  meter for

       Propeller Pump: A submersible pump with a  propeller which draws water
       through a housing. Propeller pumps are  usually high volume low head.


       Saltwater Compatible: Our saltwater-compatible  pumps are rated for long-term
       continuous duty with salt water.  Little corrosion should occur within 1 year.

       Spherical Pump: A silent pump that has only one  moving part ­ an induction
       driven impeller. Spherical pumps  have no motor shaft, seals or bearings, making
       them virtually  maintenance free.

       Trash Pump: A centrifugal pump that can pass large  objects, including sand,
       gravel and mud. Often used for dewatering  ponds.

       Vertical Pump: A centrifugal pump mounted in a  vertical direction. Vertical
       pumps usually have a long shaft with  the motor mounted above water.

Efficiency Tips

       As efficiency relates to aquaculture, pumping and aeration are the two biggest consumers of electricity. After feed costs and labor, electricity is probably your next highest overhead expense. Be careful when selecting a pump. Do not compare them by their horse power alone. What is more important is their amp usage. Often, a cheap pump has an undersized motor that must work very hard to do the job volume. This may be an appropriate pump selection for temporary or noncritical applications, but not where the lives of your animals are concerned. Often, pool type pumps when used for low pressure aquaculture applications, work with an overloaded motor.

       Operating an undersized motor in the duty range of its service factor is acceptable from the pump manufacturers point of view, but not a fish farmer's point of view. It lowers the pump's cost (which looks good to you), but it increases its energy consumption and operating temperature. Higher operating temperature shortens pump life.


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