Fluorine
PJS Element Pack Florine
5.00
PJS Calcium Cick
15.00
Fluorine
UPDATED: October 25, 2026
Fluorine (F) atomic number 9, PJS considers it to be a MAJOR element as it plays a crucial role in the skeletal development of corals, is used by other reef organisms and is above 1ppm in seawater. In the industry it is considered a trace element, we need to fix that. Fluorine belongs to the diatomic non-metal group and is naturally found in seawater. In reef aquariums, maintaining proper Florine levels is important for vitality and healthy coral growth. <br> SPS corals need the fluorine monitored and supplementation may be necessary, especially in heavily stocked tanks.
Fluorine Key Roles
Coral Skeleton Growth and Health: Fluorine is essential for the proper formation of the skeleton.
Enhanced Coral Coloration:
Fluorine supplementation enhances the blue and white colorations and fluorescence of corals.
Coralline Algae Growth:
Fluorine promotes the growth of coralline algae's, helping in Ph stability, which is what everyone wants for good reason. It is a great indicator of overall health of the reef tank; it outcompetes nuisance algae and the very visual wow factor.
Protection Against Parasites:
Fluorine helps protect coral tissue from parasites.
Skeletal Growth:
Fluorine is an essential element for the formation of the aragonite skeletons of all stony corals and is important in the coloration and vibrancy.
Skeletal Density:
It helps corals maintain a robust skeletal structure, helping in preventing brittleness.
Skeletal Structure:
Fluorine is essential as it is utilized in conjunction with other elements to form their skeleton.
ALWAYS test Fluorine 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.
Ensure the supplement is reef-safe and follow dosing instructions.
Avoid overdosing, as it can lead to imbalances and become toxic to corals and other invertebrates in your tank.
Fluorine is essential in proper strong skeletal formation.
Target a ratio of 300ppm calcium to 1ppm fluorine at a minimum.
Fluorine must be maintained along with the 5 major building blocks, as they work together in coral growth.
Low level of Fluorine lead to tissue necrosis.
Concentration window for Fluorine is very narrow, requiring constant, regular testing to maintain.
Calcium, alkalinity, magnesium and potassium levels all must also be maintained within the proper ranges as they all work in conjunction with each other and Fluorine.
Never exceed 2.0mg/L of Fluorine, the ionic balance is catastrophically compromised at this point.
Each reef tank is your work of art, and the ideal Fluorine level can vary based on many factors, such as your coral type, coral density, and your water parameters and husbandry practices.
Fluorine is depleted from your water column through various processes, such as coral growth, skimmers, and other filtration methods quickly remove Fluorine.
Clams, snails, shrimp and invertebrates use Fluorine to build, molt and maintain their shells and exoskeletons.
Rapidly growing stony corals, particularly Small Polyp Stony (SPS) corals like Fluorine and must have consistent supply of for their growth and coloration.
Strong calcium consumption, is an indicator that Fluorine is also being consumed at a quick rate as it's incorporated alongside calcium in skeletal growth.