Starry stonewort algae in hand with bulbs

Control Starry Stonewort

Many people ask how to get rid of starry stonewort. The following options can be considered for how to control starry stonewort.


Manual/Mechanical Control:

If you are considering how to remove starry stonewort, physically raking the algae can be an effective method of control.


Algaecide Control:

There are multiple options for how to kill starry stonewort that offer great control. Copper algaecides are not recommended in ponds with trout, koi, or channel catfish.


Copper algaecides:

  1. Mizzen (for ponds or lakes) – liquid that is diluted with water and sprayed over the algae, fast-acting. Re-apply when algae bloom again.
  2. Copper sulfate (for lakes) – granules that are broadcast over the algae, fast-acting.


Treatment Tips:

When treating starry stonewort,

  • If the algae are around the perimeter, treat the whole perimeter.
  • Treat no more than half the pond at a time, about two weeks apart.


Prevent Algae Growth:

There are no products available that can completely prevent algae growth. Directly managing nuisance pond algae growth through regular pond algae treatment or removal efforts will always be important for pond algae control. However, you can work to limit algae growth by reducing the nutrients that algae need to grow. Phosphorus is the main nutrient for algae growth, and removing the phosphorus from the water is a proactive effort for algae reduction.

  • PhosControl (for ponds or lakes) – granules that are broadcast into the treatment area. Bonds with the free phosphorus and some other organic materials. Use when there is minimal plant and algae growth.
  • SparKlear (for ponds or lakes) – granules that are broadcast or liquid that is diluted and sprayed into the treatment area. The beneficial bacteria dissolve the excess nutrients, fast-acting.


Additional Algae Resources:

Toxic Algae: What It Is and How to Prevent It

Is Pond Algaecide Safe for Fish

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