Algae is often referred to as "slime", "skum", or "mats". All of these terms can be correct as there many different types that can appear in your pond. When one form of algae looks like a weed, identifying what you are wanting to treat can be extremely important!
Some algae variations can be more difficult to treat than others. Ultimately, you will be using an algaecide such as Copper Sulfate or Crystal Plex. Copper Sulfate does great with thick, mat-like algae types while Crystal Plex is best used with "soup-y", more resistant algae types.
The types of algae that fall under the Filamentous group are: Horse Hair, “Moss”, and Algae Mats. The common names of these types of algae tell you a lot about how filamentous algae can be identified. Algae within this group is usually very thick and will form in mats on the pond surface. Once removed from the pond it tends to feel dry and coarse. Filamentous algae is extremely common and fairly easy to treat. The use of granular copper (Copper Sulfate), liquid copper (Crystal Plex), or a combination of both have been used to effectively treat pond algae.
The following types of algae fall under the Planktonic group: Euglena (red algae), Blue-Green (toxic algae), Oscillatoria, and Green Water. Planktonic algae is known for changing pond water color to green, brown, blue-green or even red! Planktonic algae are usually microscopic in nature and may not take on any type of form, therefore, this group of algae can’t be manually raked or removed except for Oscillatoria. Oscillatoria collects in the form of a mat on the pond’s surface but looks like snot and smells terrible!
Planktonic algae is usually the result of excess nutrients and lack of other plant competition. A liquid copper sulfate like Crystal Plex is the only type of pond algae treatment that will control these types of pond algae. Granular copper sulfate will not affect algae from the Planktonic group.
Chara is interesting because it is frequently misidentified as a weed. It appears to be rooted, has a stem, and resembles a weed more than an algae. Chara grows in big billowing puff on the pond floor and once thick enough they can breach the surface of the water. This growth has a crunchy texture and a musky odor. A byproduct of Chara is usually an extremely clear body of water. Chara is a filter algae and we highly advise keeping a chunk of Chara to ensure your pond water remains clean and clear. The most effective pond algae treatment is liquid copper sulfate or Crystal Plex. Granular copper will not treat Chara. Late in the season the algae will become calcified and treatments will be ineffective.
Seeing something different growing in your pond? Check out our ID Page or contact our office! We will do our best to help you identify what you have.