Prevent Sand Algae, Whether It’s Red Algae on Sand or Green Algae

Last Updated on July 17, 2022 by cmoarz

There is nothing worse than spending all that time curating and creating your masterpiece aquascape aquarium only to discover later that you have developed an algae problem. This can come in the form of red algae on sand or even green algae, and it can quickly ruin all your hard work.

Fortunately, there are a few things you can do to prevent and even remove sand algae from taking over your aquarium.

Why does sand grow algae in an aquarium?

Light and excess nutrients are typically the two main reasons why algae start to grow in an aquarium in the first place.

If you have too much light, or if your aquarium lights are on for too long, this can cause algae to bloom.

Similarly, if there are high levels of nutrients (nitrates, phosphates, diatoms, etc) suspended in your water, this can also lead to algae growth.

This is true for all algae, whether it’s hair algae, green algae, or any kind of sand algae.

When it comes to algae growing on sand specifically, there’s another main contributing factor, and that’s the fact that sand is a very porous material.

This means that it can easily trap nutrients and debris, which can then lead to algae growth.

But there is actually a super simple way to deal with sand algae growth and in general, it costs you nothing at all!

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A simple way to stop algae from growing on sand substrate

We know sand requires two things to grow, light and excess nutrients. But did you know you only need to cut off the supply of one of these things to stop algae growth?

That’s right, if you can find a way to block out the light, algae will struggle to grow.

And with sand algae, there’s no reason to follow a complicated blackout schedule that could harm your plants and fish.

Instead, an easy and foolproof way to achieve this is to simply turn the sand over.

As you turn your sand over more often, the algae will end up being buried and starved of light, causing it to die off.

Not only is this an easy and effective way to prevent algae from growing on your sand, but it’s also a great way to aerate your substrate and keep it healthy!

There are two ways to accomplish this:

  • Manually mix the sand around every couple of weeks. Manual removal consists of simply mixing the sand around a bit with a net or a chopstick will go a long way in preventing algae growth. You can also use an aquarium siphon with a gravel cleaner attachment. This will quickly and easily turn over the sand without you having to do any of the work! All you have to do is add it to your weekly scheduled maintenance routine.
  • Getting fish that do the work for you. No one wants extra stuff to do, so if you can find a way to outsource the task, that’s even better! There are actually a few different types of fish that love to dig through sand and will help keep it turned over for you. Bottom feeders, borrowers, and stomach slitherers all turn over sand as part of their natural foraging behavior and make great additions to any aquarium! Don’t just rely on simple algae eaters though, They likely won’t get the job done.

Does sand cause algae in a tank?

No, Sand silicate itself does not cause algae in a tank. The main causes of algae are excess light and nutrients.

The sand itself is usually a neutral inactive substrate that algae can grow in if the conditions are right.

However, sand can contribute to algae growth because it is a very porous material that can trap nutrients and debris, and sediment.

Turning over the sand regularly can help prevent algae growth by burying and starving the algae of light. Additionally, adding fish that love to dig through sand can help keep the sand turned over for you.

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Preventing algae from growing on your sand

Prevention in the first place is always better than having to deal with an algae problem later on.

Fortunately, there are a few simple things you can do to prevent algae from growing on your sand in the first place:

  • Keep the sand turning. As we said above, this is the easiest way to prevent algae from growing on your sand, But there are some other things you can do too.
  • Remove excess nutrients. If you have excess nutrients in your aquarium, it’s only natural that algae will want to take advantage of them. Be sure to do regular water changes and vacuum the gravel to remove any uneaten food or waste. If you find it’s not helping, Increase water changes by volume and how often you do them.
  • Limit light exposure. Algae need light to grow, so limiting the amount of light your aquarium gets can help prevent algae growth. If you have live plants in your aquarium, be sure to provide them with enough light for photosynthesis but not so much that it encourages algae growth. Consider setting a proper photosynthesis cycle and getting an electric light timer to auto-turn off the lights for you. Also, remember to take into account the sunlight throughout the day that your tank receives! Sunlight is very powerful compared to a normal aquarium light.
  • Get algae-eating fish. As we mentioned before, there are a few types of fish that love to eat algae. Adding one or two of these fish to your aquarium can help keep the algae population in check, But you can’t rely on them to eat it all.
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Difference between green algae on sand and slimy red algae on sand

Red slime algae are usually found in saltwater reef aquariums and is more difficult to get rid of than green algae. It’s much more aggressive and can quickly take over an entire aquarium if left unchecked.

Green algae, on the other hand, is more common in freshwater aquariums and is generally not as difficult to get rid of. It’s important to note that green algae is not necessarily bad for your aquarium. In fact, it can actually be beneficial as it provides a food source for many aquarium inhabitants. The problem with green algae is that it can grow out of control and start to smother other plants, rocks, and decorations in the aquarium. It can even remove all the oxygen from the tank.

Both types of algae can and do grow on sandy substrates. In fact, algae love sand because it’s a very porous material that can trap nutrients and debris. This is why it’s so important to turn over the sand regularly to prevent algae growth. You can’t rely on simple floss or carbon filtration to deal with these types of algae in most cases.

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What eats algae off sand?

This probably isn’t the right question to ask. There are plenty of clean up crew that eat algae, even off of sand, But they won’t ever be able to keep up with the growth if the conditions are right for algae.

So instead of what eats algae, Consider what fish turn sand over and dig around in the substrate. These fish will help keep the sand turned over and aerated, which will prevent algae from taking hold in the first place.

Some good examples of these fish are:

  • Corydoras catfish
  • Loaches
  • Goby fish
  • Burrowing anemones
  • and many more.


Algae can be a nuisance in any aquarium, But it’s especially troublesome when it starts growing on the sand. This is because algae can quickly take over the sand and smother other plants and decorations.

Fortunately, there are a few things you can do to prevent or get rid of algae on your sand. The most important thing is to keep the sand turned over so that algae can’t take hold. Other things you can do include removing excess nutrients, limiting light exposure, and getting algae-eating fish.

If you have any questions or comments, please feel free to leave them below.


Owner of and also owner of actual Aquarium Gravel believe it or not! ;). Setting up beautiful aquarium sceneries and habitats since I was very young. Enjoy!