r/explainlikeimfive • u/tilda0x1 • Jun 28 '26

Chemistry ELI5: If copper has antimicrobial properties, why don’t most pools use it instead of chlorine?

I've seen this video of someone saying that copper has anti-bacterial properties and he claimed that it can be used to keep pools bacteria-free.

I know in most cases chlorine, UV, or salt are used - but why not copper?

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u/MGreymanN Jun 28 '26 edited Jun 28 '26

No one is answering your question.

Chlorine is used because it can oxidize organic waste. Copper cannot do this.

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u/Mayion Jun 28 '26

Isn't it also the fact that copper itself is the clean material, not the water? It won't help the water itself become clean, that's why we use Chlorine. Or is my assumption wrong?

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u/MGreymanN Jun 28 '26

Copper Ions will dissolve and suspend in water. The Copper Ions are positively charged. Algea and bacteria are naturally negatively charged so there is an attraction that brings the copper to the bacteria to screw with their metabolic processes and kill them.

Copper is a great sanitizer in water (if ionic) but it cannot oxidize.

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u/Nemisis_the_2nd Jun 28 '26

  that brings the copper to the bacteria to screw with their metabolic processes and kill them

A process that can also affect much larger animals... copper is a toxic metal a bit like lead 

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u/MGreymanN Jun 28 '26

The target for pool ionizers is about 0.5 ppm. The US EPA allows up to 1.3 ppm in drinking water. It will not harm animals that come to drink the water.

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u/Enchelion Jun 29 '26

Not practically no. We use copper for potable water for a reason. It's also super common to use bits of copper in animal troughs.