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How to Remove Haze From Acrylic Aquarium

Every aquarium owner has gone through the struggle of staring at a cloudy tank in disgust. Encountering haze in aquariums is more common than you might think. Besides an immensely displeasing look, cloudy freshwater can cause various threats to the fish and the aquatic microclimate in your aquarium. Understanding how to remove haze from acrylic aquarium can be beneficial to both you and your fish.

Solving this problem as soon as possible is going to provide a healthy and thriving environment for your fish. There are a few solutions for the clearing foggy effect in acrylic aquariums. However, you first must identify why this unpleasant look occurs in your tank.

In this article, you’ll learn more about what are the causes of bacterial bloom. Discover how to remove haze from acrylic aquarium and how to keep it clean. Continue reading to learn what an acrylic aquarium manufacturer will do to provide fish with a clean and healthy living space.

Complete Guide-How to Remove Haze From Acrylic Aquarium
Source: Photo Contributor: Elizaveta Galitckai

What Causes Haze in Acrylic Aquarium

Haze in an acrylic aquarium is an exceptionally common occurrence. While many factors may cause this unfortunate issue, the chances are that you’re either dealing with bacterial bloom or unwashed substrate.

If you delay cleaning your tank from the haze, things can escalate to very undesired matters. There are times when it starts with a very subtle grayish haze, but this may quickly turn into cloudy water you can barely see through. Additionally, the bacterial growth in your aquarium can deplete oxygen, making it a dangerous environment for your fish.

So, to get a better understanding of what you’re dealing with, here are the reasons your aquarium water has turned hazy.

Bacterial bloom

When bacterial bloom or blossom has riddled your acrylic aquarium, the water is most likely going to turn exceptionally cloudy.

This issue occurs when your tank has excess fish waste, decaying food, or nutrients and a limited number of beneficial bacteria for the fish. This situation forces the bacteria colony to reproduce rapidly, causing the water to appear like a milky haze.

Additionally, these may cause a layer of bacteria on the inside wall of the tank. So, if you’re experiencing this, you might be having a bacterial bloom in your aquarium water.

Surprisingly, the bacterial bloom is a common thing. In some cases, it may look like a mild haze, while in other cases, the water may look like it’s mixed with milk. This entirely depends on how much bacteria is in your tank.

Other causes for bacterial bloom

  • The primal cause for bacterial bloom may be pouring harmful chemicals prone to kill or reduce the beneficial bacterial colony in the tank water;
  • Another result of bacterial bloom is sudden ammonia spikes from organic waste;
  • If your tank doesn’t provide enough beneficial bacteria to support the aquarium’s ecosystem while introducing a new group of fish can cause this issue;
  • A new tank that hasn’t been properly cycled may also result in cloudy water;
  • Renewing the old filter system with a new one may also cause milky water.

Unwashed substrate

Adding colorful substrates to your aquarium provides a vibrant feel to the tank’s overall appearance. However, you might notice that this may produce cloudy white water if the substrates are unwashed.

This may create residue or specks of dirt, making the water dirty or cloudy in color. In extreme cases, the tank’s wall can also showcase layers of dirt or add a gray color to your water.

Furthermore, aquarium owners should know that large pebbles do not make good substrates for your fish tank. The food you feed your fish can often get logged into these pebbles, making it hard for the fish to reach them.

The food that is stuck between the substrates will eventually produce dissolved organic compounds in your aquarium. This results in a very visible and displeasing haze. It’s best to wash sand and gravel substrates before putting them in your aquarium because it removes the fine dust.

Unwashed substrate
Source: Photo Contributor: Colin Woods

How to Remove Haze From Acrylic Aquarium

For aquarium enthusiasts, acrylic tanks are an excellent budget-friendly option. Acrylic has become the most popular material for both fish tanks and swimming pools. While it’s much more durable than glass, it may still cause cloudy water in the tank. Ultimately, you have to contend with superficial problems like haze.

However, acrylic aquariums that have a haze on the pane won’t cause any issues with the tank’s integrity. Acrylic is an exceedingly sustainable, flexible, and solid material that can endure lots of outside conditions. But, the haze may seriously limit your viewing experience and clarity if you don’t resolve this issue.

Fortunately, there are many solutions you can try to solve this issue. We’ll provide you with a step-by-step guide to help you clean and maintain your tank so you can fully enjoy its aesthetic.

Empty the tank

First and foremost, you must empty the tank before you start focusing on getting rid of the nasty haze from your acrylic aquarium. Transfer your fish from the aquarium so you don’t accidentally hurt them during cleaning. Next, you’ll need to disconnect all the power and remove any objects that are in the tank.

Once you finish this, you’ll need to drain out all the water. However, it’s important to remember that lowering the water level enough to access the haze is simply not going to work. This is because tackling haze will create tiny debris particles which may fall into the rest of the water.

That’s why it’s recommended to clean the cloudiness on a completely empty acrylic aquarium.

Use sandpaper to remove haze

Once the tank is completely empty, you can start clearing out the foggy feel of your tank. Because haze can be relatively stubborn and hard to scrub, sandpaper is an excellent option to clear every last piece of smudge on your aquarium pane.

However, you should opt for sandpaper that can cope with water and moisturizing supplements. This means that you should forget about using basic sandpaper and use one that is durable in both dry and wet conditions.

Furthermore, when using sandpaper in acrylic tanks, you should avoid making circular motions while cleaning. While you may think this is the best way to clean your tank without leaving a scrub behind, it’s quite the opposite. When applying pressure while using sandpaper with circular motions, you may leave swirl marks and minor scratches on your aquarium wall.

To remove any left marks and scratches, you may want to use other cleaning methods to get a crystal clear material.

Finishing up

Once you’ve finished cleaning the tank with sandpaper, you should now thoroughly rinse it with water and cloth. Using sandpaper while cleaning your tank can create minuscule acrylic particles to accumulate on the inside of the walls. Going over those areas with water and a soft cloth should remove the leftover particles. Besides, you may also consider using a heavily diluted detergent. 

Once you’ve finished cleaning the inside of your aquarium, go over it with a cloth again. For the smoothest results, make sure you’re polishing the aquarium with a cloth that’s lint-free and dry.

After drying the aquarium, you can return the rank ornaments and refill it with water. Now, you can let your fish swim in a clean and healthy environment.

Finishing up
Source: Photo Contributor: Elizaveta Galitckaia


In conclusion, aquarium enthusiasts can find themselves struggling to remove haze. Whether it’s from bacterial bloom or unwashed substrate, the result is most definitely unpleasing.

However, while removing haze from acrylic aquarium seems relatively easy, you need to be careful and mindful of the acrylic material. Even though this material is much more durable and solid than glass, using sandpaper may leave some marks, which can be removed using other cleaning techniques.

We hope this article has provided you with useful information on how to remove haze from acrylic aquarium.

Neal Moir

Neal Moir

is the owner at Titan Aquatic Exhibits and brings more than a decade in aquarium and acrylic pool wall manufacturing experience.

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