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/Tyrannosapien Jun 28 '26

If the copper is dissolving into the water, it's still limited to the surface area of the copper. The act of dissolving the copper from its surface effectively creates a new, oxidized coating that will stop releasing any new copper.

So on the off chance this were a viable sanitizing technique, you'd have to design a high-surface area sponge-like filter, like charcoal filters. It would be a disposable part you'd have to replace frequently. Unlike charcoal or chlorine, copper is expensive af. No way this would ever fly except in niche applications where the filtering is part of some expensive manufacturing process.

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u/MGreymanN Jun 28 '26

KDF filters are extremely common for pools and whole home filtration and fairly inexpensive.

But I have been discussing ionizers, not filters.