Lanthanum has no biological significance in reef aquaria, but can be enriched by animals in the tissue. Especially Tridacnidae giant clams enrich lanthanum strongly. In the long term this can lead to damage to cell membranes. Clams are therefore the first to die when exposed to lanthanum over a long period of time.

What’s this:

Lanthanum is a transition metal used in water treatment to precipitate phosphates from water. This process uses lanthanum chloride solutions which immediately form insoluble lanthanum phosphate in seawater. These particles must be removed from the aquarium immediately, otherwise they will sediment and later dissolve the bound PO₄³⁻.


The use of lanthanum must be slow and controlled. Excessive dosages reduce the carbonate hardness in the system, and the resulting particles can damage fish. Please follow the dosing recommendations of the manufacturers carefully and filter the resulting particles thoroughly before they can enter the aquarium. Damage to fish is always caused by excessive dosing quantities and insufficient filtering of the particles produced.


Stop the dosage, too high values occur practically only for a short time, lanthanum precipitates from the water.

Indicator species:


Value too high:

Reduce dosage, lanthanum precipitates quickly in seawater.

Value too low:

No dosage intended.

Variety transition metal
Reference value up to 20 µg/l (0,26
Skill Level orange, lowest dosages are sufficient
Source Salts, liquide phosphate-adsorber
Available Elementals La
Importance 1–6 1
Detection quality safe
Relation values none

Balling Light:

No lanthanum is dosed in the Balling Light system.

If lanthanum is used correctly, the quantities used in PO₄³⁻ reduction are usually not sufficient to cause long-term damage to the animals. Please follow our tried and tested dosing instructions. Elementals La does not consist of a pure lanthanum solution; in order to improve the effect and to prevent the formation of ultra-fine particles, a binding agent and a biopolymer are added to our product.

Lanthanum can also be used against flatworms in addition to PO₄³⁻ reduction, but unfortunately with this reef safe dosing, an effect on the dreaded Acropora flatworms Prosthiostomum (Amakusaplana) acroporae could not be observed.


If you choose to reduce PO₄³⁻ using lanthanum precipitants, keep in mind that it is always better to choose the dosage so that there is only a slight decrease in the PO₄³⁻ value. The success lies in the thorough filtering of the resulting lanthanum phosphate particles and the effect of the PO₄³⁻ reduction over a longer period of time. A reduction in the PO₄³⁻value of a maximum of 0.05 mg/l (0,26 per month is recommended. Use our Elementals La for this. This laboratory-precise mixture guarantees the safe use of lanthanum for PO₄³⁻ control.