Why is my fish tank going green within days of cleaning it?
There are a few ways to control algae. Also, monitor your lighting and excess food in the tank. Algae are mostly-photosynthetic organisms that sometimes resemble plants but are not plants, having no true roots, stems or leaves. Algae grow in freshwater and saltwater. Saltwater algae are sometimes referred to as “seaweed.” Like plants, algae require light and nutrients to grow. We supply plenty of both in our aquariums, with several hours of aquarium lighting a day and nutrients like nitrates and phosphates from fish waste. Algae come in many forms. There are microscopic, one-celled algae, filamentous algae that resemble hair, algae that grow in sheets, and macroalgae that look like plants. There are even algae that live inside the outer integument (“skin”) or calcium shell of some corals, anemones, and other sessile invertebrates called zooxanthellae. There are slimy-looking algae that are often not algae at all, but a colony of primitive photosynthetic organisms known as cyanobacteria