Questions & Answers
What causes bubbles or foam to form on my pond?
Bubbles or foam on the surface of your pond are an indication that there is excess protein in your water. The amount of bubble or foam will vary with the feeding rate. During times of heavy feeding the level of protein will increase. The protein will not dissolve in the water so it lays on the surface of the pond similar to oil. When the water is aerated or if it crashes over a waterfall air is trapped in this otherwise invisible layer that is on top of the water. When the air is trapped by the protein the bubbles or foam becomes visible to us.
Ideally, bubbles in your pond should break up within a foot or two of the base of a waterfall or aerator. If you are experiencing longer lasting bubbles then it is likely you have an excess protein problem. The presence of this excess protein could reduce the oxygenation rate of your pond. This problem is usually solved by good filtration and regular pond maintenance.
The easiest and safest way to eliminate excess protein is to perform regular water changes. If the pond can be overflowed the protein will be drawn off the surface as the water from the surface leaves. A skimmer box will tend to gather the protein and it will often collect in the skimmer box as foam which can easily be removed with a small fish net. The filter pads in the skimmer box will also trap the protein layer as it tries to pass through.
There are also foam fractionators on the market that will remove the excess protein along with suspended solids, and dissolved organic material. Foam fractionators were designed for and work best in saltwater, foam production is much easier as the salt content rises. The process uses the bubbles from a fine bubble diffuser or venturi to create foam. The foam absorbs and traps the protein and then separates the protein in a holding chamber where it can be disposed of. Foam fractionators are generally fairly expensive and their performance in freshwater has been questioned.
There are a few pond additives that will break down this excess protein. When these products are used there is always the possibility of throwing your pond into an unbalanced condition. It is important to be aware of the possible side affects of any pond additive before you use it. Then follow up by monitoring the water quality conditions of your pond.