When trying to figure out what is causing the algae problem or reduced water clarity in a pond you should try to determine where nutrients like phosphorous, nitrogen or ammonia are coming from before they reach the pond. Sometimes it is obvious like a stream or creek used to supplement the pond level during dry conditions.
Potential nutrient sources:
- Lawn fertilizer in the organic or inorganic form can reach the pond after a rainstorm or from lawn irrigation water. Avoid fertilizing within 30ft. of your pond.
- Grass clippings are a good source of phosphorous when blown into the water from lawn equipment.
- Residential flock of waterfowl contribute moderate to excessive loads of nitrogen and phosphorus.
- Deciduous leaves slowly release both phosphorous and nitrogen as they decompose on the bottom.
- Drain tiles that run from farm fields, barns, or fertilized yards.
- Streams or creeks that have muddy water transport soil particles with attached nutrients.
- Well water that originates in a subsurface organic layer often contains ammonia.
Testing the external source of water will provide you with good information to determine if is the problem. A good practice is to test the water from a stream that flows through other properties before it gets to your pond. If the percentage of nutrients is too high, you should consider diverting it or pretreat the inflow before it enters your pond.