Selecting the proper pump is essential in the success of your water feature. Depending on the visual effect you have in mind, you must match the correct flow rate to produce this effect. Too much water gives you Niagara Falls and to little, a trickle that looks like your pumps stopped up.
Submersibles:
The invention of the submersible was a real boost to water gardening. These pumps are generally inexpensive, dependable and simple to install. They are placed close to the floor of the pond and are either fitted with fountain heads or tubing that pumps the water to a waterfall or stream. The larger pumps can be adapted to do both using a flow control with adjustments for water to flow in 2 different directions. If your pond is over 3' deep you may want to consider a surface or out-of-pond in-line pump. That is not to say the larger submersibles won't work, but you may want to check flow rates, lifts and price.
In-Line Pumps:
An alternative to submersed, or in the water pumps are in-lines, or those that are located out side of the pond. The main difference is the convenience. You don't actually have to pull the pump out of the water to clean the intakes or remove for repair. The one negative aspect is that many of these pumps must be placed close to the pond in an underground chamber below the surface of the water. The reason is that if you do not want to prime the pump, then it must be below the water surface level so water is always in the lines and pump.
Connections:
Your pump must be powered or controlled by a switch in your home, out building or waterproof exterior electrical box. Let us make an obvious point. Electricity and water don't mix. That said, be sure your pump is connected to a GFCI or Ground Fault Circuit Interrupter. This will cut the power off in case the cable underwater gets damaged or a short is detected in the unit. This circuit can be in the form of a breaker on the circuit you are using, a GFCI plug located at the site or a power control center that has a long power cord and can control everything.. All cables should be buried 2' feet deep and marked so that anyone digging in the area knows there are live wires directly below. Also draw a simple map showing the location and run of the wiring. You will be glad you did somewhere down the road.
PUMP GLOSSARY;
CENTRIFUGAL PUMPS - The water is pumped by an impeller slinging the water to the outside of the volute or pump and forcing it out the discharge; you can restrict the discharge side with no ill effects.
MAG DRIVE - This describes how the motor works. It's also called "wet rotor". The rotor used by conventional motors is replaced by a permanent magnet.
DIRECT DRIVE - This is the conventional motor we all know and love and took apart as kids. The rotor is an electro-magnet turning in harmony with the electrical charge in the field.
IN-LINE - Meaning the pump can be placed outside the pond with tubing supplying water to the pump. The intake must be lower than the surface of the water, or gravity must pull water into the pump.
SUBMERSIBLE - Yes. That's it–just place your pump right in the water. You just want to protect the intake from matter that could jam or clog the pump.
VERTICAL LIFT - This is measured in feet. The distance from the surface of the water to the point of discharge. Vertical lift is also referred to as head, dynamic head or height.
HORIZONTAL FLOW - When your pump has to move water across a relatively flat area the result is horizontal flow.
DYNAMIC HEAD - Let's say your pump has to move water across your yard for 10' and then vertically up a waterfall for 3'. The total dynamic head is equal to 4': 10' of horizontal is equal to 1' of vertical.
GPH/FLOW RATE - Gallons per hour. This is the flow rate of a pump in GPH at various heights. Note on all the performance charts the flow rate diminishes as the head or height goes up. You get less and less as you increase head until "shut-off" occurs.
SHUT-OFF - This refers to the maximum vertical distance a particular pump can push water. Also known as maximum height or maximum head.
