Fluoride in the aquarium

Naturally present in sea water. In the aquarium it mainly comes from synthetic salt and tap water. Toxic in excess.

Detailed explanation

Fluoride is present in natural seawater at approximately 1.3 mg/l. It is incorporated into the coral skeleton as fluorapatite and contributes to the hardness of the calcareous skeleton.

In the aquarium, fluoride comes from synthetic salt, which usually contains adequate quantities. Tap water may contain added fluoride for the prevention of dental caries (fluoridation of drinking water).

The reverse osmosis system removes approximately 90-95% of the fluoride from the water. The DI stage removes the remainder. For this reason, osmosis water is the ideal base.

Excess fluoride can inhibit coral growth and damage invertebrates. In practice it is a rare problem because the concentrations in drinking water (0.5-1.0 mg/l) do not accumulate significantly.

Fluoride is measured only by ICP. In most analyzes it falls within standard parameters. If the value is anomalous, the first check is on the quality of the osmosis water.

Reference values by aquarium type

How it is measured

Only via ICP-OES analysis.

What happens when it is too low

Undocumented effects in aquariums.

What happens when it is too high

Possible inhibition of coral growth at very high concentrations.

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