Algae blooms develop when there is an excessive amount of nutrients (such as phosphate and nitrate) in the presence of sunlight. These nutrients come from tap water, rain runoff, fish waste, and debris. The pond may appear green or have strands of algae that float on the surface.
Establishing a self-sustaining pond ecosystem is the first order of business in controlling algae. That means that you must grow beneficial, nutrient-digesting bacteria in the pond gravel and husband plants that eat the excessive nutrients. Broadleaf plants like lilies will also shade the surface and deprive the algae of its light.
Mechanical filtration will trap debris that turns to nutrients, and recirculating the water through a pump will make it oxygen-rich. Oxygen helps the fish and feeds the bacteria which starves the algae.
Some algae-control products turn the pond dark, depriving it of sunlight. Some are actual herbicides that attack the algae.
If the problem is just too big, add a UV Pond Clarifier to your system or purchase a filter that incorporates a UV clarifier to kill algae cells as they pass the bulb.
If you need added algae control, consider adding a UV sterilizer (clarifier) to your system. Some filters come with UV Clarifiers built in , others can have a UV sterilizer unit added on.
The UV light actually emits a ray that alters or disrupts the DNA or RNA of such organisms as harmful bacteria, algae cells, parasites, and protozoa. It helps to prevent disease as well as algae.
Pond filters protect the pump from clogging from debris in the pond. More importantly, they purify the water and keep the pond environment healthy. A good pond filter will help to detoxify waste, turning it into nitrate (which feeds algae). However, the best filters will have added attributes such as UV sterilizers (to help control algae) and self-cleaning features.