Do pond pumps need to run continuously?
A9. The main reason for running a pump is to aerate the water. If you run the pond continuously, the pond will be healthier and won’t develop the unpleasant odours of toxic gases such as methane, ammonia and hydrogen sulphide (rotten egg gas). These noxious substances are produced by anaerobic bacteria (organisms that live only where no oxygen exists). The most important time to run your pump is actually in the early hours of the morning. Dissolved oxygen in the water is at its lowest level at this time because algae and plants only produce oxygen during daylight. At night, all of the living things in the pond including algae, plants and bacteria (exceot for anaerobic bacteria) are still using oxygen causing the dissolved oxygen level to drop further and further as the night draws on. If your pond is heavily stocked with fish, the early hours of the morning are when they will most need your pump to be running to supply them with oxygen. If the pond has high fish densities, the number o
