Algae on the walls of your plastic aquarium make it more difficult to enjoy your aquatic ecosystem. But the problem is more than aesthetic; while a little growth is inevitable, blooms signal that something is off with your water chemistry or other aspect of your setup. Algae compete with plants for nutrients, threatening their health, and algae can spread excessively once they get a foothold in the system. While manual removal takes care of algae currently on your plastic walls, they'll return if you don't also address the underlying cause of blooms.
Use a rubber-tipped algae scraper or a soft sponge to scrape or rub the algae off your plastic aquarium walls. Don't use metal algae scrapers, steel wool or other abrasive surfaces, as they easily scratch the plastic surface.
Remove other plastic items, such as fake plants and other tank decorations, from your aquarium. Rub them down thoroughly with a soft sponge to get off any algae growth. It's prudent to do this even if you don't see any algae on the items in case blooms are just starting out.
Add live plants to your tank. They remove carbon dioxide and nutrients from the water that algae require to grow.
Increase the aeration and circulation in your tank with a trickle filter, surface fountain, airstone, bubble wand or other suitable accessory. More oxygenation and water movement make it harder for algae to become established.
Test your water chemistry and address elevations of ammonia, phosphate, nitrate or other nutrients algae feed on. Make sure your filter and protein skimmer are clean and functioning optimally, and that you're not overfeeding your fish, since uneaten food breaks down and releases nutrients for algae. Check for dead fish, invertebrates or plants in your aquarium -- they give off ammonia and other nutrients as they decompose.
Change fluorescent light bulbs if they're more than a year old and VTO bulbs if they're more than six months old. Their wavelengths alter over time, and current algae growth on your plastic aquarium walls undoubtedly like the wavelengths where they are at present.
Block your tank from receiving direct sunlight. Limit use of your tank light to six to eight hours per day. Most algae thrives with lots of natural or artificial light.
- While certain changes to your tank setup help prevent algae growth, remember that the needs of your fish, invertebrates, plants and coral come first; don't take away special lighting or make other changes that may negatively affect your aquarium life.
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Eric Mohrman has been a freelance writer since 2007, focusing on travel, food and lifestyle stories. His creative writing is also widely published. He lives in Orlando, Florida.