Pond season is back upon us. And with it, the same pond problems we face year after year. But there are answers, and I’ll try to shed some light on those in this column.
The problem I’m asked about most often is algae. Green water. Pea soup in the back yard. Surprisingly, it is a very easy problem to fix.
In the past, there were easy and effective treatments that would kill the algaes with environmental poisons like copper sulphate. These have been banned, because they can get into our water system.
To solve a problem, it is important to identify the cause. There are three main things that can cause an algae problem. Light, food and phosphates.
Light can be difficult to control. If you placed the pond in an area of shade, you did well. Reduced sun makes algae control a lot easier. Using floating plants can cut down the light entering the pond, and reduce the algae bloom. Hyacinths, Water Lettuce, Pond Lilies are all great choices to reduce light infiltration. These plants actually compete for the same food resources that the algae needs. There are also strong dyes that you can add to the water, which make the water blue, and reduces how deep the light can penetrate the water, reducing the algae’s access to light.
Food for algae is basically a combination of fish waste, leftover food and debris that fall into the pond. Filters can help a lot in reducing these foodstuffs for the algae, by removing solid waste with mechanical filtration and breaking down the liquid wastes with biological filtration. The moving water also increases oxygen levels, which also can help fix algae problems.
Phosphates are easy to control with certain materials that can be added to your filter. Our tap water contains phosphates, so if you are using tap water to fill and do water changes, you have to make sure these materials are changed regularly. Phosphates act like an on/off switch for algae, removing phosphates is the most effective way we have now to control algae.
Filtration is the best and most effective solution for algae control. A properly designed filtration system can make your pond a beautiful addition to your living space. It can be utilized as part of the water features, the pump powering water through filters and then to the top of a water fall, or through a fountain.
A well designed filter system includes a mechanical filter, a biological filter, an option for chemical filtration and most important for algae control, UV filtration. A mechanical filter is usually a sponge that can be removed and cleaned to take out particulate waste, the chunks. This is important when using pond clarifiers that clump the algae, also known as flocculants. Biological filters take advantage of bacteria to reduce waste buildup. Chemical filtration includes phosphate removers discussed earlier and activated carbon that removes colours and odours. Ultraviolet (UV) filters pass the water over a source of UV light, that exposure kills suspended bacteria, parasites and algae completely. Installed properly and kept clean, these filters can give you crystal clear water that is a joy.
A well designed pond can give you a lot of enjoyment thoughout the outdoor season.