How to fix green aquarium water

Green aquarium water is caused by free-floating single celled green algae.With the correct conditions single cell green algae is very prolific. So prolific that there are literally billions and billions of the green algae free-floating in your aquarium water, enough to cause your water to turn green.

The most common cause of green water in your aquarium is direct sunlight hitting your tank or a very bright sunlit room. The first step is to reduce or eliminate the sunlight that is hitting your aquarium or entering the room.

If this is not possible then you may want to consider relocating your aquarium somewhere else in your home. If relocating the aquarium is not desired or is impossible you can use a UV sterilizer to control the algae. We'll get to that later.





If you have no sunlight entering the room where your aquarium is located the aquarium light bulb might be the cause. If this is the case try replacing the aquarium light bulb with a light bulb designed for color enhancing aquariums, make sure it's not a light bulb for growing aquarium plants.

In some cases reducing the sunlight and doing a few extra water changes with a gravel cleaner will fix this problem. If you've tried that and you still have green aquarium water try using a product that you can purchase from a pet store that will clear the water. Add the water clearing product to your water. Water clearing products or flocculants bind the microscopic single celled algae together forming larger particles of algae, large enough to settle to the bottom of the tank under gravity.
Once the water has cleared do a 25% water change with a gravel cleaner and rinse out your filter media (remember not to rinse your filter media under tap water).
The reason for the water change and rinsing out your filter media is we're trying to remove as much of the algae is possible. Leaving large amounts of decomposing algae on the bottom of the aquarium will potentially cause another algae bloom. Repeat that step every couple of days for up to a week.

If you're still having problems with green aquarium water and you do not want to relocate your aquarium then try a UV sterilizer. Most UV sterilizer manufacturers 100% guarantee that their product will clear the suspended algae from your aquarium. I personally have never seen a case where a UV sterilizer that has been set up properly was unable to clear the aquarium water. A UV sterilizer is basically a tube with a germicidal UV lamp inside of it. the aquarium water is pumped through the UV sterilizer, the intense UV light produced by the germicidal UV lamp kills / vaporizes the signal celled algae. The end result in every case is crystal clear aquarium water regardless of how much sunlight is hitting your aquarium. Depending on the area you live in UV sterilizers start at $60 and up. Another benefit of the UV sterilize your is its ability to destroy free-floating disease causing parasites and protozoa.Uv sterilizers are very commonly used in saltwater applications to control disease.