String Algae

How to clean up String Algae

String Algae is a filamentous algae that can grow in your pond.  It grows in long strands as it filters nutrients out of the water so It prefers areas of the pond where the current is the greatest, usually in the waterfall/stream or near your skimmer.  While it isn’t particularly harmful it is unsightly and most pond keepers want it out of the pond.

Eliminating string algae is not a one-time thing.  It is usually a process that can last several weeks to months.

Before starting any treatment for string algae the first step is to manually remove as much of it as you can from your pond. Using your hand, a stick, or very carefully, a rake, you can twist the algae around like a fork in spaghetti and then pull it out of the pond.

The next step is any or all of the following:

Install a biological filter that grows beneficial bacteria that eat the same nutrients as algae so that you are starving the algae of food.

Add aquatic plants that compete for the same nutrients and starve the algae as well as shading the surface of the pond and depriving the algae of sunlight.

Using an algaecide in your pond once a week, while the water is cold is very effective.  We recommend *CleanMax+*.

When using an algaecide it is important to calculate the volume of your pond. Over application of algaecide can result in fish death.  To calculate the volume of your pond you multiply the average length x the average width x the average depth x 7.5 and you will have your pond volume in gallons.  Apply only enough algaecide for the volume of your pond.  You can also use a weaker dose of algaecide but never use more.

Algaecides reduce the oxygen in your pond and fish need oxygen to breath so make sure your waterfall/stream is running to add oxygen to the water.  Always use an algaecide in the morning and never at night, because your pond has less oxygen at night.  Your fish can suffocate if you use an algaecide in the evening.

Cold water holds more oxygen so treating for string algae now is better than when the water warms up.  We suggest that you never use an algaecide when the temperature is higher than 70 degrees.

Stop by our nursery at Falling Water Gardens and pick up your cleaning supplies and talk with our sales representatives about proper usage.