Is water exchange necessary for ponds?
A19. Yes. In time, heavy metals, phosphorus and other undesirable substances accumulate in the pond. The best practice is to vacuum the bottom of the pond with a pond vacuum, regularly (weekly, monthly, quarterly – depending on the pond’s needs and the enthusiasm of the owner). Small, cheap vacuums which work off garden hoses are available from pond and swimming pool shops. If the pond is above ground, you can siphon the sediments off with a hose. Don’t remove more than 25% of the water so when you top up the water quality doesn’t change too much and overly upset the established ecosystem. Ideally, if the top-up water is chlorinated, it should be “aged” for a day or two in an open tank to allow the chlorine to gas off. Otherwise, spray the water into the pond to aerate it to remove as much chlorine as possible and add chlorine neutralizer at the same time. If you don’t regularly vacuum the pond bottom, you should clean the pond out completely once or twice a year, or once every two yea
