The solution is to let nature fight the battle
One popular method, widely used is to reduce the amount of light from entering the pond by using a DyoFix pond dye, another is by the introduction of a natural bacteria, ByoFix.
Bacteria are single-celled organisms and one of the earliest known forms of life on the planet. Although impossible to identify all bacterial species, thousands have been studied and despite the negative perception, the majority of bacteria are not harmful and are widely used in industrial, domestic and natural applications, by exploiting their natural metabolism. Bacteria, like people, carry out two types of metabolism: anabolism, requiring energy to build useful complex molecules, and catabolism, the breakdown or digestion of complex molecules. Digestion involves decomposition of organic materials ranging from natural wastes to chemical by-products. Bacteria become particularly attractive in the purification process of rivers, streams and lakes. These processes can be the solution to returning an aquatic environment back to its original conditions purifying contaminated water.
The natural bacteria contained in ByoFix typically replicate on average every 20 minutes in a logarithmic growth pattern. One cell will divide reproducing two new daughter cells. After 12 hours its calculated there will be approximately 70 billion cells. ByoFix introduces millions of bacteria at the start of the process. The numbers become colossal, the bacteria spread, start to break down the excessive organic matter and nutrients. Water quality begins to improve, notably the water becomes clearer and any odorous gases given off will diminish