AcroPower supplies amino acids that corals need to build their skeletal architecture. Like other cnidaria, corals have a special ability to uptake dissolved amino acids across their entire surface. Closed system aquariums with protein skimming and other ULN (ultra-low nutrient) filtration methods deplete amino acids that are vitally important for coral health. Corals become more colorful within days due to the extension of the growing margins when AcroPower is used. 250 ml, 500 ml, bottle.