My copper ion level is above 0.4ppm. What should I do?

Copper in your pool or hot tub is beneficial for fighting algae if it falls within the ideal range of 0.2 ppm to 0.4 ppm. However, if your copper level exceeds 0.4 ppm and remains unchecked, you may start to notice water coloration that leads to stains.

Copper Test for Pools and Hot Tubs

First things first, you need a good copper test. Check the expiry date on your test, as they’re only valid for 2-3 years. Additionally, most test labs at pool stores are only accurate for copper levels up to approximately 0.5 ppm, making them unsuitable for testing low levels of copper. We recommend these copper test strips.

Pool copper test strips
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How to Reduce Copper in Pools and Hot Tubs

Eliminate the Copper Source

If your copper level is reading around 1.0 ppm or higher, the first step is to eliminate the source.

Turn off or remove your pool ionizer
Remove any mineral cartridges (e.g. Frog or PoolRx)
Stop using copper-based algaecides

Copper Under 1.0 ppm: Add a Chelator

Chelator products will keep the copper dissolved in the water and prevent it from staining. We recommend Think Minerals Copper Control.

The copper level will naturally come down on its own once the source is removed; however, it will take several weeks. Test for copper every week to track the progress.

Copper Over 1.0 ppm: Add a Sequesterant

If your copper level is above 1.0 ppm, we recommend using a sequestering chemical, such as The Magenta Stuff, to remove it from the water altogether. This chemical will neutralize all new minerals for up to 6 weeks.

If you add a sequesterant to a pool with an ionizer, be sure to leave the ionizer removed or turned off, because the minerals will be neutralized, and the cell or electrodes will be depleted with no benefit.

Copper Stains

Copper can stain if the level exceeds 1.0 ppm and the pH is out of range, or if certain shocks or sanitizers are used. Copper stains can be either blue-green or black in color. Copper Control can be used to remove copper stains from pool surfaces and equipment. Follow the directions on the package or here.

High Copper with a Pool Ionizer

If you have a ClearBlue Mineral System or other pool ionizer and find that your copper level exceeds 0.4 ppm, it’s acceptable as long as it remains under 1.0 ppm and the pH is within the typical range of 7.2-7.6. However, you are using up your mineral cells faster than necessary.

With a ClearBlue system, if your copper reading is between 0.4 ppm and 1.0 ppm, unplug it or set the Maintain (Ion/Action) setting to 00 for 2 weeks, then retest. If it’s back in the 0.2 ppm to 0.4 ppm range, set the Maintain setting 25% lower than it was. For example, if it was set to 50, turn it down to 37. Test for copper every week or two and adjust the settings further if the copper level continues to increase.

Heater Corrosion Adding Copper

If your copper level continues to increase despite removing all sources of copper, there is something else in your pool or hot tub setup that is causing the copper to accumulate. This is usually caused by the heater, which typically has a copper or brass core. If your heater is old or the pH level in your pool or hot tub has been consistently high or low for an extended period, we recommend contacting your pool or hot tub technician to inspect the heater.