Thrive Strontium is designed to increase strontium in your reef aquarium. Some reef aquariums will need supplementation of strontium for stony corals to thrive. Strontium is used by both SPS and LPS corals in calcification. Corals and calcerous algae use strontium to grow, just as they use calcium and alkalinity. Adding strontium has been shown to increase coral growth. Anyone who is keeping organisms that deposit calcium carbonate skeletons like SPS and LPS corals may need strontium.