Selenium
PJS Element Pack Selenium
5.00
Selenium
UPDATED: October 2, 2025
Selenium (Se) atomic number 34, PJS considers it to be a Trace element as it plays a crucial role in the biological and metabolic process in corals and is used by all reef organisms and is measured by ppt in seawater. Selenium belongs in the polyatomic non-metal group, along with calcium, sulfur and phosphorous and ALL are naturally found in seawater. In reef aquariums, maintaining proper selenium levels is important for skeletal, biological, coral color, vitality and healthy coral growth, and supplementation will be necessary, especially in heavily SPS stocked tanks.
Selenium Key Roles
Coral Skeleton Formation:
Selenium helps in proper skeletal calcification, formation and tissue basal connection.
Biological / Metabolism:
Selenium is essential for metabolic processes and enzyme production. It is used by zooxanthellae in photosynthesis. Selenium is required for conversion of nutrients, fatty acids and proteins to energy process for living things for growth , tissue repair, digestion, reproduction and must be maintained with all other within this group.
Selenium is metabolized by corals and by all organisms in the entire ecosystem including denitrification and conversion fatty acids to energy.
Enhanced Coral Coloration:
Selenium is used at a cellular level enhancing vivid coloration and intensity of corals.
Aids in UV protection for corals and zooxanthellae.
Protection Against Parasites:
Selenium supports the overall health, promoting resistance to parasites.
ALWAYS test selenium levels in your reef aquarium before supplementing to determine if dosing is needed to avoid overdosing.
Start slowly by beginning with a low, gradual dose over days avoiding any sudden shifts in water chemistry and monitor the effects.
Avoid overdosing, as it can lead to imbalances and become toxic to corals and everything in your tank. LPS and SPS corals selenium is essential in controlled levels. Selenium is essential for corals to spawn. Selenium is essential for many metabolic processes and enzyme production. Selenium is used by all living organisms, aiding in a balanced eco system. Selenium is highly recommended for high PAR lighting. Selenium has high antioxidant properties. Foods may contain levels of selenium that can influence your parameters. Dosing selenium, more is not the answer, time is the answer. Dosing selenium in conjunction with amino acids and nutrients is essential for proper utilization. Dosing selenium can influence consumption of iodine, calcium and many other elements. Deficiency will lead to reduced and improper growth, sensitivity to lights, imped the ability to produce or consume nutrients, impacting the symbiotic relationship of corals and zooxanthellae. Overdosing will lead to tissue damage, tissue detachment and coral bleaching.