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Pondspectives with Mike

Are Copper Ionizers Safe for Aquatic Life?

By Mike Garcia

Current Controversy: Are copper ionizers safe for use in fish and plant water features?

It sounds simple. Just plug in the copper ionizer and enjoy an algae-free pond. Are ionizers safe for fish ponds? What about water gardens? Doesn’t copper kill aquatic life?

All heavy metals are bioaccumulates that the body cannot remove from the liver. Over the long term, heavy metals become toxic to organic life. Water features such as non-life-supporting fountains use ionizers successfully, but are ionizers fish- and plant-safe?

Some people feel that with proper supervision, ionizers show long-term benefits to aquatic life. As with other treatments, if used improperly ionizers can cause major problems with pond fish, aquatic plants and water quality. Ionizers must be well-supervised in pond applications with fish and plants.

If the directions and care are followed, then the pond will benefit from ionizers. International Accredited ALS Laboratories performed tests on the absorbtion of ions within pond fish, specifically within their tissues. The test results showed that the pond fish exposed to .1 to .3 parts per million of copper, .01 to .03ppm of silver and .01 to .03ppm of zinc contained minimal ion absorption within their tissues, and they remained unaffected.

On the flip side, heavy metal accumulation leads to immunosuppression and can result in pond fish suffering from bacterial infections for no apparent reason. Sometimes initial water quality is optimum but low levels of copper and/or zinc are present. Metals are most toxic in low alkalinity and pH. This accumulation immunosuppresses the pond fish and allows normal pathogenic bacteria to gain an advantage leading to ulceration.

What are your experiences with ionizers in ponds?

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Are Copper Ionizers Safe for Aquatic Life?

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What type of fish was the testing done on? Comets have a much lower tolerance than koi for copper toxicity and other heavy metals. What about other life in the pond - frogs, tadpoles, fish fry, insects such as dragonfly larvae, birds and other animals that drink the water, etc.? What about long term effects? These products have not been used in ponds for a long period of time yet. Sean, Marlborough, MA Posted: 11/26/2011 6:22:25 AM The results of the tests performed by ALS are less than definitive. Based on the copy that I have seen, total exposure time of the test fish to the effects of the ionizer are not listed. Also absent are the water quality parameters on the test holding facilities, most notably pH and water hardness. Without these and other crucial items included in this report, the results have no practical value. Meyer, Pensacola, FL Posted: 11/22/2011 5:51:47 PM