Sometimes, water changes don’t solve all of your aquarium’s problems. Outbreaks of diatoms, dinoflagellates, hair algae, Aiptasia anemones, and even cyanobacteria can still occur despite large and frequent water changes, and in some instances it may make the issues worse. That’s where filtration media, certain additives and medication come in to play. Water changes represent a one time reduction in nutrients through dilution, but things like fish food and various fish and coral metabolic byproducts constantly add those unwanted nutrients and toxins back into the water. Things like carbon, filter pads and socks, GFO, and protein skimmers constantly remove these unwanted substances, helping to keep the aquarium clean between water changes. Unfortunately, even a combination of water changes and these filtration aids won’t always fix the problems. When the situation is this severe, medications and other extreme substance may have to be used, but please do so with caution and avoid it if possible.