An addition, not a replacement
An ionizer releases copper ions into the water; some systems also release silver ions. They can help control algae and some microorganisms, but you still need to maintain the required primary sanitizer level and pH.
Pool care
Water chemistry and equipment
Copper pool ionizers: what they can and cannot do
Copper and copper–silver systems can help control algae. You still need effective filtration, balanced pH, a primary sanitizer and regular water tests.
How they work
How do copper pool ionizers work?
Electrodes gradually release metal ions into the water as it circulates through the system. Copper helps control algae; some units also release silver ions. An ionizer can supplement routine maintenance, but it does not make a pool chemical-free or eliminate water testing.
These ions do not act equally quickly against all microorganisms and do not provide the same residual protection as correctly dosed chlorine or bromine. The CDC therefore treats copper and silver ionization as a supplemental process, used alongside the required primary sanitizer.
Mainly used to control algae
Copper is mainly used for its algaecidal effect. It will not quickly clear an established algae bloom, correct poor filtration or remove the organic waste left by a busy day of swimming.
Test the copper concentration
You cannot judge the copper level by looking at the electrodes or the water. Use a suitable test, check pH regularly and stay within the limits specified by the manufacturer.
Too much copper can cause stains
High copper levels, particularly with unsuitable pH or oxidation, can stain pool surfaces and equipment or discolour hair. Do not combine a copper-based algaecide with an ionizer without checking the copper level and the product instructions.
Before buying
What to ask the supplier
Be wary of claims that an ionizer completely replaces chlorine. Ask for specific concentration limits, testing requirements and installation instructions.
- 1Ask for the technical manual, electrode specifications, testing instructions and the manufacturer's target copper range.
- 2Check the required flow rate and where the unit must be installed relative to the filter, heater and chemical dosing equipment.
- 3Keep sanitizer and pH within the required ranges. An ionizer does not remove the need for regular water testing.
- 4Do not add a copper-based algaecide until you have tested the existing copper level and checked the ionizer instructions.
- 5If stains appear or the water changes colour unexpectedly, stop adding copper and test the water before making any adjustments.
Is it suitable for your pool?
When an ionizer may help
When it is worth considering
An ionizer may be useful if your filtration works well and you test regularly, but algae keep returning. You must also monitor copper levels and maintain the electrodes as instructed.
Problems to fix first
If the water is cloudy, the filter is neglected, pH is unstable or sanitizer is too low, fix those issues first. Adding an ionizer will not correct poor circulation, filtration or water treatment.