The effect of rubidium is somewhat controversial. There are virtually no studies of its biological function. It is generally assumed that rubidium is only absorbed into the coral skeleton because its similarity to potassium. Recent studies have shown that rubidium plays a role in the repair of damaged cells. To what extent this also applies to corals, however, is not yet known. In our experiments, however, we could observe a better color shine and harder skeleton formation of corals if the value of rubidium was kept stable.

What’s that:

Rubidium is a non-essential microelement, but has a hardening effect on the growth tips and the coral skeleton.




Insufficient levels reduce the hardness of the coral skeleton.

Indicator species:

None, possibly soft growth tips on hard corals, but this might also be caused by too low concentration of fluorine and/or strontium.

Value too high:

Rubidium has no proven biological effect on corals. However, we have found that coral skeletons harden better and colours appears to be more brilliant. Too high values practically never occur. Therefore, always verify a too lugh measuring value.

Too low value:

Dosing Elementals Rb or partial water change with Professional Sea Salt is usually sufficient.

Variety Heavy metal
Default value up to 150 µg/l (0,26
Skill Level Red, only for experienced aquarists
Source Salt, supply systems trace element mixtures
Available Elementals Trace Rb, Balling-Light-System. Feed
Importance 1–6 2
Detection quality middle

Balling Light:

Rubidium is added to the aquarium via the Trace Elements and Professional Sea Salt. ICP tests for Rubidium are not performed because the measurement quality is too poor for this value. We supply Rubidium in concentrations similar to nature, this is done automatically in our systems via Balling Light and the subsequent systems.


Rubidium dosing seems to be particularly effective for corallimorphs. Especially lovers of “Bounce Mushroom” should have a look at this.