Pretty much every aquarium owner will at some point have experienced the issue of green water. This can develop quickly, with a tank looking clear and healthy one minute, before turning dark green in just a few days. Before you start carrying out a full water change or looking to replace a filtration, you need to understand the root cause of the issue.
Green water is caused by a particular type of algae growth. Unlike algae varieties that colonise the glass sidings of your aquarium, green water is caused by phytoplankton. Although this variety of algae causes no immediate danger to your fish, it does prevent you from enjoying your aquarium.
Particularly dense algae blooms will also limit the amount of light penetrating into your aquarium water, which will eventually impact your fish and plants.
Causes of Algae Blooms
One of the main causes of algae outbreaks is excessive UV light. Just like other types of plants, algae thrives on UV light. Avoid placing your aquarium close to a suntrap and make sure you are not leaving UV lights on for longer than is recommended. Algae growth may also be caused by an imbalance of nutrients within your aquarium.
The main substances that contribute to algae growth are phosphate and nitrate. These can find their way into your tank water from decayed food and fish waste, but can also be found in regular tap water. An efficient tank filter will usually keep on top of this issue, while regular water changes will also help.
How to Avoid Algae Outbreaks
If you are struggling to keep on top of algae outbreaks, you may need to reconsider the type of aquarium light you are using. If you only have a small fish tank, avoid using a UV light designed for use with a much larger aquarium.
You should also ensure you are not running your UV light 24 hours a day. Most aquariums will only need around 10 hours of UV exposure per day, even if they are home to marine plants.
You will also need to up your game when it comes to aquarium maintenance if you want to keep on top of algae blooms. Frequent water changes will ensure the substances that facilitate algae growth are kept to a minimum. You may also want to test replacement water for phosphate and nitrate prior to adding it to your tank. Investing in a new filtration system is also something to consider, especially if you find that your existing filter cartridges are quickly becoming clogged with debris.