Brightwell Aquatics Boost pH+ is a high range pH increaser for all marine aquaria. Allows maintaining a pH of 8.3, 8.4 or 8.5 in difficult tanks without raising alkalinity (when used as directed). Increases pH in marine and reef aquaria without affecting alkalinity or calcium level on properly buffered tanks (which is an unusual ability not found in most similar products). Works with buffers and alkalinity products to increase pH to desirable 8,3, 8.4 or 8.5 levels without increasing alkalinity itself (in marine aquariums that have a proper alkalinity of 7.7 to 10 dKH). 250 ml. Thought to assist coral growth. Anecdotal evidence shows higher pH allows increased growth rate in new frags and mother colonies in coral growout facilities.