Pond foam is caused by surfactants which are attracted to the surface of air bubbles and strengthen the bubble so it does not pop, but creates an unsightly foam. These surfactants may be artificial chemicals such as detergents. However, the most common cause of pond foam is high levels of protein, from the partial breakdown of organic matter, building up in the pond.
There are a number of products available which are effectively wetting agents, which affect the surface energy of the bubbles, causing them to pop, and therefore break up the foam. However, it is also necessary to find the cause and eliminate that also. We also recommend the following:
- Carrying out water changes to dilute the surfactants.
- Removing excess sludge from the bottom of the pond.
- Checking that the fish stocking level is not excessive; maximun of 60cm of adult fish (i.e. 6 x 10cm fish) to every square metre of surface area.
- Adding Sludge Buster to remove dead organic matter.