Red Algae, also known as red slime algae, is actually not an algae at all. It is a cyanobacteria. It’s fully photosynthetic, and can be extremely difficult to manage once it gets out of hand. The reason that Red Algae is such a common problem is due to the fact that many aquarists aren’t checking the levels of nutrients in their aquariums as often as needed.
How can I get rid of my Red Algae problem?
Nutrients: The two main nutrients you need to keep an eye on are nitrates and phosphates. Both of these are constantly being produced in the aquarium. Fish waste, fish food, pretty much anything that is rotting in your aquarium contributes to nitrates and phosphates. The more food you feed your fish, the more waste there will be. Try feeding less food in longer intervals. You should also manually remove as much of the algae as you possibly can. With Red Algae, it shouldn’t be too difficult. They form carpets which can usually be removed with ease. Scrape rocks, pumps, glass and any other surface that has algae growing on it. Be sure to remove floating bits of algae too. While you’re at it, you might as well clean up the uneaten food resting on the floor of your aquarium, too. Nitrates are generally removed by performing water changes, so do these on a regular basis. Aim for a reading of zero.
Lighting: Light bulbs that hang over your aquarium should be changed at least every six months. As light bulbs age, the light emitted from them will gradually change spectrum. In the red spectrum is where most pest algae, such as Red Algae, truly thrive. To reduce the chance of red algae growth, try cutting down the amount of time you leave your light on.
Water Flow: Red Algae grows poorly in fast-flowing water. If you take a look at where the algae is growing in your tank, it is probably in an area without much water flow. To try to eliminate and prevent growth, you must add water flow to these parts of your tank as soon as possible.
Most importantly, be patient. Don’t expect results after only a few days. Removal of Red Algae takes weeks of constant care.