Filtration - There are many types of filters available at various price points, two of the most common being sand filters and biofilters.
Another good filter application for architectural water bodies is a Horizontal Sub-Surface Flow (HSSF) wetland. This is a constructed wetland where water is passed through a course gravel filter bed that’s planted with wetland plants and grasses. The gravel filters out particulates and also provides a large surface area for beneficial bacteria to grow, providing biofiltration. In addition to removing particulates, the wetland plants also remove nitrogen and phosphorus. By removing nitrogen and phosphorus, the available food source for algae is reduced.
Another important aspect of circulation and filtration is skimming the surface of the water with pond skimmers. Skimming provides a mechanism for removing floating debris, oils and algae. By removing this debris, you can reduce the work- load of the microorganisms that would otherwise have to break down these materials once they sank to the bottom of the water body.
Aeration assists in maintaining the proper level of dissolved oxygen (DO) and oxidation reduction potential (ORP) to reduce and break down excess organics. Aeration can be accomplished in several ways. Two of the most common ways include an aeration unit (i.e., a pump or blower) that can be used to introduce a column of micro bubbles to the water body; and a cascading waterfall, which introduces air as the water bounces around the rocks and falls into the pond. These mechanisms provide the added benefit of additional water circulation, particularly with an air column. With an air column, a vertical circulation cell is created that helps break up the stratification layers that can occur, especially with deep water bodies.
The introduction of an oxidizer into the airflow will also help ensure water quality. Ozone is a powerful oxidizer that kills the organics that adversely affect the water balance. It can control algae growth and help prevent algae blooms from forming. Ozone also breaks down into oxygen, which further increases the oxygen levels. Applying ozone is safe for aquatic life, but it must be applied in proper doses.
3. Water Management
The final key to water quality is the management of the water as it enters and leaves the water body. Most water leaves the system by evaporation. Therefore, in most architectural water bodies, the biggest long-term factor affecting water quality is the buildup of precipitates of salts and other elements left behind when the water evaporates. Some of these elements can be removed through filtration, but in severe situations the only way to remove them is to replace a volume of water. A regular schedule of replacing the water is the best method for maintaining the level of these elements. This can be accomplished by providing an overflow stream that dumps to a storm drain. If the water body is large enough, overflow could be used as a source for irrigation, as opposed to allowing the water to go to the storm drain.