Trace elements are often overlooked in reef aquariums because they are required in such small amounts compared to the more common Alkalinity,  Calcium and Magnesium. However, they are essential for coral health and balance.

Corals use certain elements, such as Strontium, Boron, and Barium, in the formation of their skeletons, which strengthens the calcium carbonate structure they rely on for growth. Elements like Iron, Manganese, and Selenium support the zooxanthellae within corals, allowing them to photosynthesize efficiently and provide energy. Many trace elements also influence coral colouration. Iodine, Manganese, and Potassium are tied to pigmentation and fluorescence, meaning stable levels can bring out vibrant colours. On a cellular level, trace elements help corals process nutrients, build proteins, and regulate metabolism. Others, such as Selenium and Iodine, provide protection from oxidative stress, strengthening coral immunity against strong lighting, shifting parameters, and disease challenges.

In aquariums, these elements are gradually depleted by corals, bacteria, and filtration systems. Water changes help to restore them, but in systems with fast coral growth or high demand, supplementation is often necessary. This is why many reefers turn to trace element dosing systems from brands like Coral Essentials, Triton or Aquaforest.

It’s important to remember that trace elements are a double-edged sword. A deficiency can lead to weak growth, dull colours, and stressed corals, while overdosing risks toxicity, tissue loss, or algae outbreaks. The safest way to manage them is through ICP testing, which shows precisely which elements are out of balance so dosing can be targeted rather than guesswork.

Below we list trace elements that we stock along with their importance to a reef aquarium.