Sodium Carbonate Peroxyhydrate Algaecides

Aquatic Sodium Carbonate Peroxyhydrate Algaecides for Lakes and Ponds

Sodium carbonate peroxyhydrate (SCP) was first registered with the EPA in 2002. It is a granular product that is used in lakes as an algaecide. SCP is created from sodium carbonate and hydrogen peroxide. It is sold under the trade names Phycomycin®, GreenClean®, PAK™ 27and EcoBlast™.

Aquatic Use and Considerations

SCP is used to treat filamentous algae and cyanobacteria. Cyanobacteria are the bluegreen algae that can cause scummy blooms that can potentially contain toxins harmful when ingested. Green algae may also be affected, but lower doses may selectively treat cyanobacteria but not the green algae. SCP can also treat liverworts and mosses, but is not labeled for vascular plants. There is some evidence that higher application rates may inhibit growth of coontail (Ceratophyllum demersum).

When applied to water, SCP becomes sodium carbonate and hydrogen peroxide. The hydrogen peroxide oxidizes the algae, and kills it. The SCP action will be obvious in 5-10 minutes after treatment, and there may be some fizzing from the hydrogen peroxide.

SCP can be used to clear algae-filled water as well as to prevent the growth of algae in the first place. This feature separates it from other chemicals used to treat algae such as copper products, which are used to reduce algae blooms but do nothing to prevent additional algal growth.

When used to treat an algal bloom, considerations must be taken to prevent unsafe drops in oxygen concentration in the water that can be harmful or lethal to fish and other aquatic life. Applications should be made early in the day. For heavy blooms or large waterbodies, treat no more than ½ of the waterbody, and wait at least two days to treat the remainder of the waterbody. Treatment of some cyanobacteria may result in release of toxins due to the rupture of cells.

Due to potential effects on beneficial invertebrates, it is not recommended to apply this product in waters where biocontrol is occurring for invasive plants. This could include native or stocked populations of the milfoil weevil (Euhrychiopsis lecontei) which controls Eurasian watermilfoil (Myriophyllum spicatum) as well as the loosestrife beetle (Galerucella calmariensis) which is used to control purple loosestrife (Lythrum salicaria).

The use of SCP may cause increases in water alkalinity and pH, although the extent to which this occurs in natural waterbodies following treatments at application rates has not been studied.

Forestry Distributing Knowledge Base

Biology and Control of Aquatic Plants 
Sodium Carbonate Peroxyhydrate Chemical Fact Sheet

Note: Products may not be registered for use in your state or locale. Check to be sure a specific use pattern is approved in your area before use. Check product labeling or your local state agency for more information. Most current product labels are available by visiting the product manufacturers website or at https://www.cdms.net