Guide: How To Clear Up A Cloudy Fish Tank

Below, we have compiled two videos and a few tips to show you how to clear up that cloudy water in your fish tank,

This first video from Howcast gives us an excellent idea of the causes and how you can prevent cloudy water zombie fog.

Video: How To Clear Up A Cloudy Fish Tank

What Causes Cloudy Water In Your Fish Tank?

Many things can cause the water in your aquarium to get cloudy, but the most common are:

Bacteria bloom – Note that a bacteria bloom will be a cloudy white. If you notice a greenish color to the water, you may have an algae issue.

You want to decipher between green water and cloudy, milky water. Cloudy is usually bacteria driven. Green is usually algae driven. – Howcast

If you think you may have an algae problem?
Click Here: To see our post on how to prevent and eliminate algae in your fish tank. 

Too much maintenance. Cleaning your filter, significant water changes, or gravel cleaning can unbalance your aquarium.

When this happens, bacteria can take up in the water and start feeding off the nutrients now floating in the water column.

Typically, the water will settle with time and the milky appearance may disappear. However, you can take steps to speed things up one of two ways;

You Can Try A UV Sterilizer

A UV Sterilizer will stop the bad bacteria by using ultraviolet light to cause mutations in the bacteria’s genetics so they can’t reproduce. In most cases the UV sterilizer will create crystal clear water conditions within 3-6 days.

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COODIA Internal Green Water Killer Filter Aquarium Tank U-V Pump

• Turns green water to clear in 3 to 7 days.
• Suitable for Saltwater and Freshwater
• Clean up to 75 gallons tank
• Built in 5 watt water pump
• 5 Watt U-V bulb inclu

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Watch the video below where you can see time-lapse video of exactly how a UV Sterilizer works, day 5 is amazing.

Will a UV Sterilizer Clear Up Cloudy Water? (Video)

Below is an excellent video from Eddie’s How To’s that shows us actual time-lapse proof over a five period how a 9Watt SunSun UV Sterilizer eradicated the cloudy water in his fish tank.

Note: @1:55 you can start to see the transformation and @2:14 you can see the complete transformation where the cloudy water is gone.

Video: How do You Clear Up a Cloudy Fish Tank?

You Can Add Some Beneficial Bacteria

Seachem Stability Fish Tank Stabilizer – For Freshwater and Marine Aquariums 500 ml

• TANK STABILIZATION: Seachem Stability will rapidly and safely establish the aquarium biofilter in freshwater and marine systems, thereby preventing the #1 cause of fish death: new tank syndrome.

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Adding beneficial bacteria to your aquarium will help colonize beneficial bacteria in your gravel, rocks, plants, filter media. This beneficial bacteria will eventually out-compete the harmful bacteria for the nutrients now in the water column.

After the cloudy water is gone, if you still notice some particles floating around, you can add a coagulating agent like Seachem Clarity, which will cause most of the particles to stick together and allow your filter to pull them out of the water.

Otherwise, keep to your weekly maintenance and everything should balance itself out.

Further Reading: Do You Have More Problems? We Put Together A List Of The Most Common Aquarium Problems Along With Their Causes And How You Can Fix Each Problem.