How To Clear Cloudy Aquarium Water from Sand: Keep Your Fish Tank Clear

6 min read


Many aquarium owners opt to use sand as a substrate in their fish tanks. Sand is not without its upsides, but it does have one glaring downside: your fish tank may become cloudy after adding sand.

A cloudy tank from sand can be pretty unsightly. It’s important to keep your tank as clean as possible, but sometimes, sand can make it pretty difficult.

Here are a few things you can do to help clear cloudy aquarium water from sand:

  1. Wait for the debris to settle.
  2. Run the water filter.
  3. Add water clarifiers.
  4. Wash the sand.
  5. Change the water.

Read on and find out the benefits and drawbacks of using sand substrate in fish tank and how to clear a cloudy fish tank from sand.

Using Sand Substrate in Fish Tank

While most aquarium keepers go for gravel, some find sand to be more alluring as substrate.

First off, many find that sand better mimics the natural habitat of fish. After all, river beds and ocean floors are mostly covered with sand, and rarely with gravel. Your fish will feel more at home when it sees sand below it.

It will look more natural and give off a beach vibe to your aquarium, which many are fond of.

And while gravel will collect dirt and debris within its spaces, sand will effectively keep it at the top. This makes it easy to clean; you also don’t want the trapped organic waste to decompose and release ammonia into the tank.

However, waste collecting on the sand will not be a pretty sight. Moreover, it’s not easy to vacuum sand as it has a tendency to get sucked into the vacuum.

Complicating things further, the sand substrate can get easily disturbed and may not stay in place.

And lastly, coming back to the topic of this post, your aquarium can get cloudy after adding sand, which may hide your aquarium from view.

Can You Add Fish to Cloudy Sand Water?

This is a concern you may have: will cloudy water from sand hurt fish?

Truth be told, sand is not going to be that harmful to your fish. We’ve already seen that sand is part of fish’s natural habitat, so adding fish to cloudy sand water is not exactly going to be a death sentence.

That being said, sand can cause irritation to fish’s gills as well as their fins, especially if we’re talking about fine grains, so it is not a good idea to subject your fish to it.

Look at it this way: you’d probably survive inside a room full of dust, but you wouldn’t like that experience, would you?

As a matter of fact, sand can cause more damage to your filter than to your fish when it gets sucked into the filter and clogs it.

Even if we leave aside all the harmful effects of sand, cloudy water does not make your aquarium look appealing – and an aquarium is all about appearance isn’t it?

How to Clear Cloudy Aquarium Water from Sand

These tips can help you clear cloudy aquarium water from sand. I’ll walk you through the options from easiest to hardest, so you can decide the best way to help clear up your tank.

1. Wait for the Debris to Settle

Cloudy water can be caused by dust and sand that is supposed to lie at the bottom floating around in the water.

Is your aquarium water cloudy after a water change? When you add sand or water to your tank, it can easily get mixed up, but gravity will help settle things eventually. If you are not in a rush, you can wait it out. The sand should all sink to the bottom of the tank within 24 to 48 hours, clearing up the water.

If this does not work, or you want to clear it up faster, check out the next few steps.

2. Run the Water Filter

All fish tanks need a water filtration system. If you’ve just begun to set up your tank, adding sand and water and nothing else, it might take longer for the sand to settle and clear out of the water.

Making sure you have an effective filter set up and running is the next step to clearing up your tank and keeping it clean. Filters work by drawing in water and debris from the tank, and running them through a series of filter materials like floss and sponges that will trap dirt, dust, and debris.

Then the filter recycles the clean water back into the tank. Running the filter will help clear a cloudy fish tank from sand by filtering out any sand that does not sink.

If this is not working, you may want to change your filter floss or sponges to ensure your filter is functioning effectively. If this isn’t enough, try one of the following steps.

3. Add Water Clarifiers

If your aquarium is very cloudy after adding sand, you may need to take even more steps to help clear up the water. There are chemicals called clarifiers that you can add that will help clear the water by causing particles to clump together. This will make them heavier and fall to the bottom, making your water less cloudy. The clumps can then be easily filtered.

Acc Clear clean cloudy aquarium water

Water clarifiers are pretty easy to find at the pet store, or you can order them online. API ACCU-CLEAR Water Clarifier (available on is an example of an easy-to-use at-home clarifier.

If patience, filtration, and clarifiers still aren’t doing the trick, you may need to check out the next few steps.

4. Wash the Sand

One reason your fish tank may be cloudy after adding sand is that you did not wash the sand enough before putting it in. For any substrate that you add to a fish tank, you should try to wash it thoroughly. Sand will have dust and dirt in it when you buy it, so you want to run it under water multiple times until the water runs clear.

If you did not wash your sand enough before adding it to the tank, you can empty the water out and clean the sand at the bottom. Then, add the water back carefully.

Hopefully, the washed sand will not make the water as cloudy, but you may still have to wait for it to settle again to be completely clean.

5. Change the Water

If all of the above steps fail, there is a chance that the sand itself isn’t the cause of the cloudiness, and another problem exists. Fish tanks need a delicate balance of good bacteria to help keep the water healthy for the fish, but bacteria can over-grow. It could be that some disturbance has released a lot of nutrients from the sand into the tank, causing an explosion of bacteria.

Sometimes the only way to treat problems with your tank’s bacteria is to drain the water out of the tank, replacing it with new, treated water.

Changing the water in your tank can be a big undertaking, and it is important not to disrupt the healthy tank bacteria or pH balance when you do. Therefore, you should only consider this step if all other measures have failed and you have waited several days.

Final Thoughts

Using sand substrate in fish tank can make your water cloudy, which is not something you’d like.

Clearing up cloudy aquarium water from sand can be as easy as doing nothing or be a very involved multi-step process. What interventions you choose to take will depend on whether or not there are fish in it already and how long you are willing to wait.

You shouldn’t take any chances when the health of your fish is at stake. Take prompt action to get rid of the sand from the water.

Follow these steps to clear the water of sand so that your beautiful aquarium comes into complete view again.

Thanks for reading.


Written by:

Pet Aquariums

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