Fluorine is used for the targeted supplementation for the reef aquarium where depletion has been detected below that of natural seawater levels from your ATI ICP test

5ml of Fluorine to 100 litres of aquarium water will increase the fluorine concentration by 1 ug/l 

Fluorine is useful for the coral calcification process but care should be taken when raising fluorine levels and we recommend only dosing at 1ml per 100 litres of aquarium water to start with and see where you are on next ICP test and increase slowly from thereon