A Beginners Guide to Algae
The nemesis of all aquascapers, both new and experienced, is algae. This is a brief guide to help understand how algae can appear in a planted aquarium, and how it can be treated.
To put it simply, algae appears when there is an imbalance between lighting, nutrients (fertilisers) and CO2 (if applicable). If there are more nutrients in the water than the plants need for photosynthesis, algae will begin feeding on the excess nutrients and start to multiply. That is why it is crucial to keep up with regular water changes in a planted aquarium, especially in the early stages when there is a low plant mass, to prevent these excess nutrients from building up. Adding the right amount of fertiliser can take a little trial and error, as what is recommended on labels doesn’t always take into account the actual plant mass of any individual tank. It’s best to air on the side of caution, start with lower doses and keep an eye on the tank. If the plants seem deficient, add a little more. If algae is appearing, add less.
Lighting also plays a large roll in having a balanced, algae free tank. If your light is too strong, or on for too long, you will start to see algae. A tank with a large plant mass can handle strong lighting and for longer periods of time. If starting a new tank, it is recommended to start out with a 6-hour lighting period and gradually increase is it the plants grow in and require more light.
Co2 can also play a roll in algae growth. If you are using Co2, it is important to make sure you have good water circulation, or ‘flow’. This is to ensure that Co2 is being distributed evenly throughout the tank. Co2 levels should not fluctuate. It is recommended to set the Co2 to switch on one hour before the lights come on. An easy way to make sure you constantly have the correct levels of Co2 is to use a Co2 dropchecker.
If you are making changes to your tank due to algae, it is best not to make a lot of changes at once. Changing one thing at a time will help you narrow down what it is exactly that is causing the imbalance.
It should also be noted that filtration can play a big roll in keep planted tanks healthy, balanced and algae free. The best size filter for a planted tank is one that has a flow rate of at least 8-10x the tank’s water volume. It is important to remember that a filter’s actual flow rate is usually about half its advertised flow rate. For example, a 60L aquarium would require a circulation flow rate (flow inside the tank) of about 480L. The UNS Delta 90 has a maximum flow rate of about 950L. The circulation flow rate would be about half of this, making it an ideal size for a 60L aquarium.
