Filtering your pond water to directly compete with duckweed for nutrients is measurably effective, economical and low maintenance. We have field tested and monitored all kinds of methods and contraptions for removing duckweed but have settled on reducing the nutrients that these plants need to be susstainable. Our filtration system evolved from university research and time spent in field working with materials and products to learn what works and what not to do. We have learned that filtration often needs to be combined with other biological products to obtain the best results. That being said, we have recorded excellent results with just filtration for reducing duckweed growth.
The filtration system that we have developed is a recirculation system position outside of the pond and requires the use of a small electric submersible pump. The water from the pond is pumped into a shallow basin where it comes in contact with media that supports a colony of algae and returns back to the pond. The species of algae are non invasive and more effective at removing nutrients than the duckweed ( competitive exclusion). This will not cause the pond to be covered with algae, which is only second worst to a pond covered with duckweed.
Some of the things we have learned:
- Algae growing in these filters continue to work all year. Stays alive at -19 degrees Farenhite.
- We have filters working on ponds that are over eight years old.
- Pumps do need cleaning and may need replacement after awhile.
- The media in the filter basin can increase the PH value to reduce ammonium which is the preferred form of nitrogen for duckweed growth.
- Algae rapidly removes phosphorous from the water in the filter.
- Filters may need to be inoculated with algae when extreme heat occurs due to stress.
- Larger filters provide better results due to media surface area. Up to one acre is possbile.
We sell a filter in a box that is adequate for ponds up to three quarters of an acre in size. We can help you design and install a filter system if your pond is larger.