Strontium is probably important for accelerating coral and calcareous algae growth. NSW (Natural Sea Water) contains approx. 7 - 9 mg/L strontium. This strontium is associated (”chelated”) with sulfate. Since the growth of corals and calcareous algae goes hand in hand with strontium and calcium depletion, depletion of calcium (which is very easily measurable) usually means depletion of strontium as well. About Natural Strontium: Strontium supplements should be designed in such a way that a too low or a too high strontium concentration is avoided. With this supplement we have reached this aim with an easy-to-use formulation. Initial strontium concentration can easily be maintained when dosing the same amount as our Coral Calcium. This reduces the need for a strontium measurement. This supplement contains predominantly strontium sulfate together with some other ingredients to avoid an ionic imbalance. This sulfate form is significantly more effective and less toxic than the commonly used strontium chloride. Furthermore strontium is present in natural sea water as the sulfate just like this supplement! Also, all ingredients are of a pharmaceutical quality or even better. This ensures that no unwanted elements are added to your valuable aquarium. Some other requirements: The use of Coral Calcium as a calcium supplement is highly advised. In fact this Natural Strontium and Coral Calcium are designed to be used together for excellent results. Directions: Shake before use. Regular maintenance: Dose the same ml’s as Coral Calcium.