Stunted coral growth and the presence of unwanted algae is commonly an indicator of excessive phosphate in the water. Phosphate is a consequence of fish waste and while phosphate is essential for life, too much is detrimental. Phosphate is often also present in tap water, so can be inadvertently introduced during water changes.
Anti-Phos is a fast-acting, easy-to-use liquid formulation of lanthanum that rapidly detoxifies phosphate, removing it from the water. Anti-Phos should be used whenever high phosphate is detected and following water changes to remove phosphate found in tap water.