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Copper Ionization for Water Sanitation

By, Dr. Ratus Fischer

Fischer EcoWorks 

How it works

Copper ions are copper atoms stripped of two electrons (Cu++). In their ‘desire’ to acquire the missing electrons, copper ions easily bond to organic molecules, such as cell walls of pathogens. In the course, they damage the cell walls and kill the organisms.

Copper Ions are created by a DC current flowing between copper electrodes in the water stream. Each copper ion released is ‘free’ copper, as opposed to ‘bound copper’ that is not aggressively seeking bonds. Free copper ions are relatively stable in water and travel throughout water systems, especially recirculating systems, killing pathogens, preventing algae and biofilm.


Only in the past few years have copper ionization systems come on the market that automatically control the copper output to the flow rate and the EC (electrical conductivity) of the water. This has made copper ionization a predictable means of pathogen, algae and biofilm control. Avoid systems without this active control. They are suitable for swimming pools and fish tanks, but not for most greenhouse applications with varying conditions.

Free copper concentrations of 1 ppm will inactivate pythium, phytophthora, xanthomonas and other waterborne pathogens while 2 ppm will kill algae. This means that most copper applications are still within the U.S. drinking water standard of 1.3 ppm.

Free copper seems less vulnerable to degradation from organic water in the water than chemical oxidizers. This makes it valuable in treating recirculated or pond water.

While chlorine has a very small window between effectiveness and plant toxicity, copper has not shown to be toxic even in 10-fold overdoses. Excess copper does not accumulate in the plant; instead it will be strongly bound in peat soil mixes.


Copper ionization lends itself as a first-tier defense against disease because it is extremely residual. Investment costs per gallon are lower than UV or ozone, while operating costs (replacing copper electrodes around once a year) rank between UV/ozone and the high operating costs of chemical oxidizers.

There are no restrictions on releasing copper-treated water at the recommended concentrations into the environment or sewage systems. But as with fertilizer water, it is prudent to avoid point discharge of copper-treated water.



Water Education Alliance