String algae are unsightly and can cause pond owners a lot of extra work.  So, where does this stuff come from and how can you control it?

String algae is a plant that grows in long strings or hair-like filaments.  It can get quite long and makes thick mats flowing over rocks. Because it is a plant, it requires certain things- sun, water, and nutrients.  If even one requirement is missing, then the algae cannot grow.  That is the key to controlling string algae.

In a pond situation, the only variable we can control is the amount of nutrients floating around in your pond water.  The nutrients feed string algae. Hot summer days, also, cause algae to grow even faster!

Ways to Control String Algae​

1. Clean your pond! Remove the muck, dead leaves, and plant matter releasing nutrients as they break down. Remove the nutrients before the algae begin to grow.

2.  Don’t overfeed your fish – The extra food releases more nutrients.

3. Clean your filter pads and check your bio-falls for sunken leaves.  For Minnesota ponds, it is helpful to watch when the tree blossoms drop in spring. We remember to remove autumn leaves but the flowers and tree seeds can leach nutrients just as quickly! Flower drop is usually around Mother’s Day in the Minneapolis/St. Paul area and maple seeds drop a few weeks after that

4. Check for nutrient “sources” other than plant matter.  Take a hard look at the area near your pond.  Does water run off your lawn into the pond?  Is there a low spot where rain water pools and drains into your pond?  Rain water and lawn runoff are sneaky sources of nutrients.

5. Treat string algae outbreaks with these fish safe products:mEcoBlast– is an “on-contact” treatment. First pull off as much string algae as you can then treat the remaining algae stuck to the rocks with EcoBlast. It may cause your water to be foamy for a while but once the treatment has worked the water will clear up.  The foam is oxygen bubbles released as the EcoBlast attacks the algae. SAB Stream & Pond Cleaner is a combination of beneficial bacteria and enzymes which clean the water.  These cleaners help break down organic debris and balance biological life in the pond.  It also contains a phosphate binder to minimize algae growth. In some cases, simply using an algaecide like Aquascape’s  fish safe algaecide, works well to control string algae and smaller “green water” algae. Algaecide kills algae. It doesn’t remove the excess nutrients so your pond may experience a second “algae bloom” worse than the first one.
If your pond is struggling with string algae issues, check out our Pond deep clean process or contact us to schedule a deep clean!  Cleaning your pond can be done any time of the year!