Antimony in a saltwater aquarium and its importance

Table of Contents

What is ANTIMONY (Sb)?

Antimony (Sb, Latin: stibium) is a silvery shiny metalloid, meaning it exhibits properties of both metals and non-metals. It occurs in the Earth’s crust, mainly in the form of ores such as stibnite or ullmannite. Antimony and its compounds are toxic. It primarily exists in oxidation states of -III, +III, and +V, and sometimes +IV in chemical compounds, forming sulfides (Sb2S3 i Sb2S5), oxides (Sb2O3 i Sb2O5, Sb2O4), chlorides (SbCl3, SbCl5) and antimony hydride (SbH3).


Importance of antimony in seawater

Antimony is one of the undesirable elements. Its presence in water can have a negative impact on marine animals. Antimony serves no biological function and is toxic. There are bacteria that can metabolize it, however, its presence in a reef tank indicates contamination.

Dangers related to the presence of antimony in seawater

The presence of antimony in saltwater is undesirable. Its high level can lead to health problems in corals and other animals, and even to their death.

How to protect your aquarium?

It is important to regularly monitor the level of antimony and keep it at an undetectable level – 0 μg/L. The absence of antimony in saltwater ensures the health and beautiful coloration of the animals.

The most accurate and reliable method for determining antimony is through ICP-OES analysis. Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) is the most precise analytical method for analyzing the elemental composition of saltwater.


To ensure the appropriate level of antimony in the aquarium, you should systematically test it and maintain the correct level. If the level of antimony remains high for an extended period, it can lead to health problems for corals and other animals and even their death. The most common causes of exceedance of antimony:

  • contaminated salt,
  • tap water,
  • cement,
  • frozen food.

Find and eliminate the cause of the problem and reduce the value of this parameter in the water. Execute up to 6 water changes. It is recommended that during each change, approximately 15% of the aquarium water volume should be replaced until the recommended value of this parameter is achieved. The water prepared for the change must have the appropriate target salinity level. Use salt with the right parameters and composition suitable for conducting an ICP test. You can also use zeolites as filtration media.


Antimony is an element with toxic properties. High concentrations of antimony in saltwater aquariums can be harmful to marine animals, including corals, leading to their death. Regular ICP-OES tests, identification and removal of sources of contamination, and remedies such as water changes are crucial in maintaining a low level of antimony.

About author

Picture of Magdalena Metzler

Magdalena Metzler

Privately, I am a mother and a lover of nature and sport. My main interest is quantum chemistry, which hides a whole lot of unsolved mysteries and connections, which is extremely exciting from a scientific point of view.
In my scientific career, I have conducted international projects focused on innovative solutions for many branches of business, e.g. automotive, construction, and now, of course, marine aquaristics.
Working at Reef Factory gave me a passion for marine aquaristics, which I can develop every day, building a chemistry department and creating products that will help aquarists take care of tanks and ensure the highest safety of animals. One of the most exciting memories of working at Reef Factory is the commissioning of the ICP-OES spectrometer, which analyzes the elemental composition of seawater. The method of analysis in ICP is based on an analytical technique, which is a combination of my passion for quantum chemistry and marine aquaristics.
I hope you find my articles on ReefPedia interesting and helpful! Happy reading :))

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