Water features such as a pond can create a peaceful haven in the garden. If you want to keep the plant life and fish in your pond healthy, you will need to add a pond pump to circulate the water, so it does not become stagnant. When you are choosing pond pumps you will need to consider the following. pond pump 1. All of the water in your pond should be pumped every two hours. This means all the water is circulated 12 times a day, which is good for the plants, fish and filters in your pond. You will need a flow rate of 3,000 to 4,000 litres of water an hour for a 6,000-litre pond and a 2,000-litre pond would need between 700 and 1,600 litres. 2. Waterfalls are an impressive addition to a pond, as people like the sound of running water. You will need to work out the volume of water needed to create an impressive waterfall. You need about 250-350 litres of water per hour of flow per inch (2.5cm). A waterfall with a wide lip will use more water than one with a narrow overflow edge. The ideal height for your waterfall is between 40cm (16 inches) and 90cm (36 inches). 3. Pond pumps are designed to work in harsh outdoor conditions, so buy one which comes with at least a two-years guarantee. Do not use a small water feature pump. 4. If you have fish, a pond pump must be able to run 24 hours a day, 365 days a year, without fail. 5. It is best to use two pond pumps to save money and have back-up so your fish don’t suffer if one fails. 6. Take the time to understand about maximum flow and pressure for your pump so you don’t end up buying the wrong one. 7. Always measure the height you want to pump water to from the surface of the pond and not the bottom. 8. You will need to think about the running costs too, which you can calculate yourself. The wattage used by the pump is usually stated on its box. If not, look for the amps used on the label attached to the body pump itself. You can convert amps to watts by multiplying amps x volts. For example, if your amp is .2 and your voltage is 220, then that is 44 watts. This also means the pump will consume 44 divided by 1000 units of electricity per hour (1 kWhr = 1 unit) To work out the costs, use the following formula: Cost per year = "Y" Pump power = "W" Watts Pump runs "H" hours per day Cost per unit of power ="C" in pence Y=[W/1000 x Hx365 x C/100] in pounds a year.