How to Clear Green Aquarium Water?

Wondering how to clear green aquarium water? Click and learn all about how to get rid of outbreaks caused by the sudden expansion of suspended algae.

It is completely natural for aquariums to have some algae. In fact, algae can provide food for aquatic creatures in your collection. However, the problem arises when things get out of control and the water turns cloudy and opaque.

The green color of the water in your aquarium occurs because the number of microscopic algae becomes so large that it reduces the transparency of the water. Is this problem solvable at all?

Keep reading to find out all the details on how to clear green aquarium water.

Green Water In Fish Tank – Causes

Has a similar situation ever happened to you? Your aquarium is running smoothly, the water is clean and your aquarium pets are happy. Then, out of the blue, it all became discussing pea soup.

The water has become disgustingly green, so much so that you can’t see anything. “Green Water” outbreaks are caused by the expansion of suspended algae known as phytoplankton. The problem with this type of algae is that they multiply by billions in a short period of time, and thus a phenomenon called “blooming” occurs.

These are the most common causes of green water outbreaks.

Excessive Light

Like all other plants, algae love light. However, as usual, excessive light in the presence of nutrient sources can send algae into hyperdrive. This can happen due to placing the aquarium on a sunny window, leaving the tank light on for too long, or using a light that is too strong/inadequate for your fish tank.

Read more about The Best Aquarium Light To Prevent Algae

Nutrient Imbalance

This is also one of the segments that can lead to this condition of your aquarium. Namely, overfeeding and/or having too many fish for your tank size or filter capacity which ultimately results in the accumulation of nutrients. Also, if you fill your aquarium with nutrient-laden tap water, it will have the same effect.

Poor Maintenance

Poor maintenance habits cause a gradual deterioration in water quality. It doesn’t look so terrible at first, but it soon creates an ideal environment for algae to grow. Accumulation of nutrients, dirt, buildup, fish waste, etc., often results in fish disease or algae blooms.

how to fix green aquarium water

How To Stop Fish Tank Going Green

These are the basic steps you can take to prevent green water outbreaks.

Proper Lighting

As already mentioned, exposure to direct sunlight is not desirable. If you can’t avoid it, it would be good to install background material or draw the shades during the daytime. This will eliminate a significant amount of light.

Also, choose a light that is appropriate for your aquarium. You can even install a timer to control the number of hours the light is on and for a consistent day/night cycle.

Good Maintenance

If you want to provide a healthy habitat for your aquatic pets, regular water changes should be an essential part of your routine. Therefore, try to do 10% weekly or 25% bi-weekly water changes.

In addition, vacuum uneaten food and other organic material, as well as gravel. Also, don’t forget to change the filter cartridges once a month, and service the canister filters regularly.

It may sound difficult and complicated, but a clean tank is a healthy tank.

Water Testing

Test your aquarium water regularly for nitrate and phosphate. If you use tap water, it is also a good option to test it before putting it in the aquarium tank. You can also use reverse osmosis (RO) or deionized (DI) water if your tap water contains high nitrate or phosphate levels.

Stocking & Feeding

Too much fish and food in the aquarium can cause an increase in nitrate and phosphate levels. Therefore, keep 1 inch of adult fish per net gallon of water. Also, feed only what your fish can eat in 2 minutes or less once or twice a day.

How To Fix Green Aquarium Water

UV Sterilizer

Installing an ultraviolet sterilizer is a great way to deal with green water in an aquarium. As water passes through the UV chamber, all algae and various pathogens are eliminated. The best thing is that ultraviolet sterilizers are completely safe for fish, invertebrates, and plants.

Eliminate Lights

As already mentioned, too much light is often the trigger for green algae blooms. One way to solve this problem is to turn off the lights completely and wrap the aquarium in a black plastic bag, blanket, etc.

In the vast majority of cases, algae blooms will die within a few days. Finally, if you don’t see results within 48 to 72 hours, you will need to find some other solution.

Diatom Filter

Although many consider them expensive and old-fashioned, the Diatom Filter works pretty well. Namely, this type of filter uses diatomaceous earth to trap microscopic particles (suspended algae) creating clear water.

Chemical Treatment

If you have tried all the above steps and have not found the answer to the question “how to clear green aquarium water”, it is time for chemical treatment.

The most important thing to emphasize is that this should be the last option as it doesn’t solve the cause of the problem, and you can never be sure of their effect on the fish, plants, or the balance of your aquarium.

If you opt for this type of treatment, remove the filter medium; in addition, try to maintain good water circulation in the aquarium and dose according to net gallonage.

To Wrap Things Up

In general, green water is usually the result of either significant excess light or a major water quality problem. Although it may look terrible, you don’t need to panic. It is not toxic to your aquatic world unless it reduces the amount of oxygen available in the water. With proper maintenance techniques, this problem is very easy to solve.

Do you have any tips and tricks for how to clear green aquarium water? Let us know in the comments below.

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