Why does the water in your turtle tank turn green?

As a turtle keeper, chances are high you've encountered what every turtle tank owner dreads: green water. If you've ever wondered just why your turtle tank turned green, keep reading. Discover what causes green water, why it happens, and how to remedy the situation so your turtle can swim in clean water.

What causes the water in a turtle tank to turn green?

Green water, or an algae bloom, in a turtle tank is typically caused by too much light, too many nutrients, or improper cleaning. The good news? All three of these causes have relatively easy solutions.

How to Fix Green Water in a Turtle Tank

Bodies of water, including turtle tanks, are subject to algae blooms. Also sometimes called "pea soup," these outbreaks are typically caused by a drastic increase in the amount of suspended algae or phytoplankton. Although it's impossible to totally eliminate algae, too much can be hurtful to a turtle's overall health. But don't fret. If your tank frequently turns green, we've got nine ways to prevent this from happening.

1. Ensure your turtle tank has plenty of room

Algae grows in turtle tanks because it feeds off the nutrients in turtle waste. If the tank is too small, this can cause the nutrients to become more concentrated and the algae to bloom. How big should your turtle tank be? That depends on how big your turtle is, but the general rule is that the tank should be at least 10 gallons for every inch of the turtle's shell. If you have the space, a bigger tank may help reduce algae. Here's how to choose an aquarium and how to set up a reptile tank.

2. Select the right tank filter

If you have frequent algae blooms, check your tank filter — it may not be working well. Not sure of what filter to choose? Here's a guide about how to pick the best filter for your tank. You can also ask a pet store or consult with a customer service rep to ensure the filter you've purchased is perfect for your tank. Also, replacing filter cartridges every month is also a good idea.

3. Ensure the lights aren't left on for too long

Turtles need plenty of light to thrive. On average, reptiles need 8 to 10 hours a day. Once your turtle has received this much light, it's important to shut off the lights at night, as excess light can encourage algae growth. Consider adding a timer to help give your pet the proper day/night cycle it needs. The Zilla 24/7 Power Centers are safe power strips that contain seven outlets to help you set timers for lights, heaters, and filters.

If your tank is by a window that receives natural light, it's best to move the tank away from the window. (Note: The type of light your pet turtle gets matters. Learn more about how to choose the best light to meet your reptile's needs.)

4. Keep the tank clean

Proper maintenance is necessary to ensure the tank's water quality is high. Changing the water regularly can help keep algae at bay. About once a month, you should change 25% of the water and replace it with fresh. What's key here? Ensuring the phosphate and nitrate levels aren't too high. Algae feeds off both nutrients.

It can be a good idea to fully clean a turtle tank — taking everything out and washing the tank with soap and water — about every four to six weeks.

5. Water testing

Regularly testing the water for phosphate and nitrate is a smart bet. If you find high levels of those elements in tap water, you can use deionized or reverse osmosis water. Also, river and lake water includes minerals needed to keep your aquatic turtle healthy. Add Aqueon Water Renewal to the tank to replace those minerals.

6. Pay attention to mealtimes

Algae also can feed on turtle food. If you find your turtle leaves plenty of food behind, adjust the levels so there's less food left after eating. Since turtles tend to eliminate where they eat, pick up any leftovers after your turtle eats. Consider using a net to clean up any waste left behind.

It's important to note that if your turtle isn't eating as much as he or she typically does, it could be a sign your turtle is sick. If their lack of appetite persists, consider taking your turtle to the veterinarian.

7. Install a UV sterilizer

Consider installing a UV sterilizer like the Coralife Turbo-Twist Ultraviolet Sterilizer on the turtle tank to help remove algae. When the tank's water passes through the UV chamber, the algae is removed along with other disease-causing organisms.

8. Live plants

Another way to prevent algae blooms is by adding live plants to your tank that consume the same nutrients as algae. Some examples include floating plants, like hornwort or duckweed. Before you add any plants to your turtle's tank, it's important to ensure the plants are safe for your turtle to eat because not all plants are safe for turtles.

9. Chemical treatments

Chemical solutions should always be your last line of defense against algae blooms since they don't tend to address the root cause of the problem. However, algae removers are a good tool to have in your toolkit. Be sure to carefully follow the instructions when using algae remover.

Fixing Green Water in a Turtle Tank Is Simple

Although algae blooms, or pea soup, in a turtle tank are relatively common, it's also a problem that is easy to fix. By using one of the tips we've given, you can have a sparkling clean turtle tank and one happy pet.