Ozone in the aquarium
Powerful oxidizing gas used to sterilize water and improve its clarity. Effective but dangerous: must be used with ORP controller and activated carbon.
Detailed explanation
Ozone (O3) is a molecule composed of three oxygen atoms. It is a very powerful oxidant that destroys bacteria, viruses, parasites, dissolved organic compounds and water colours.
In aquariums, ozone is generated by an ozonator and injected into the skimmer (the most common method) or into a dedicated reactor. Ozone reacts with contaminants in water by oxidizing them.
The benefits are notable: crystal clear water, reduction of bacterial load, elimination of yellowish colours, improvement of redox potential (ORP). Many professional aquarists consider ozone indispensable.
The dosage is controlled via the ORP potential. The ozonizer is connected to a controller that measures ORP and activates the ozone when it drops below a threshold (typically 300-350 mV). When the ORP reaches the target (350-400 mV) the ozonizer turns off.
Residual ozone in the air is toxic to the respiratory tract. The skimmer must have an activated carbon filter on the air outlet. The treated water must pass through activated carbon before returning to the aquarium to eliminate residual ozone.
Excess ozone (ORP above 450 mV) is lethal to fish and invertebrates. The ORP controller is mandatory, not optional.
Ozone is not for beginners. It requires an investment in controller, ozonator, activated carbon and an understanding of the chemical principles involved. But for those looking for maximum water quality it is an irreplaceable tool.
How it is measured
Controlled indirectly via the ORP potential. Target: 350-400 mV.
What happens when it is too high
ORP above 450 mV: Toxic to all organisms. Turn off the ozonator immediately.
Coralia Lab monitors this parameter with AI diagnostics. Tank Score alerts you when a value moves outside the recommended range for your aquarium.
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