When you have a build-up of unsightly foam and froth on the surface of your pond which is due to an excess of protein in the water.
Foamclear will breakdown the froth, allowing good gas exchange between the water and air and helping to maintain the correct pH.
If there is a lot of foam constantly present, check the efficiency of the biological filtration system using NT Labs Ammonia and Nitrite Test Kits, and reduce the amount of food fed. Also add Mature to boost the activity of the filter system, and perform a partial water change.