Picking the best aquarium water clarifier will make your fish tank look clean. You would be able to see all the activity going on inside. Not every water clarifier is suitable for fish tanks. Choosing the wrong clarifier may kill your fish.

In this guide, we will see some of the best aquarium water clarifiers. We have tested multiple products and gone through various customer reviews online and in-person to cover it all for you.

So, let’s begin!

Comparison Chart

Products Bottle Size Suitable for Usage period

8 ounces Freshwater tanks Weekly

19.1 ounces Freshwater tanks Every 5 days

10.5 ounces Freshwater tanks Daily

8 and 16 ounces Fresh and saltwater tanks As needed with a gap of 6 hours

The Best Aquarium Water Clarifiers

1. API Aquarium Water Clarifier


  • Suitable for freshwater fish tanks.
  • Conveniently clarifies cloudy water.
  • Easily clumps any floating particles.
  • Works fast and improves filter efficiency.
  • Suitable for weekly use.


  • Requires a UV light for 100 percent results.


This is the best aquarium water clarifier that you will find on the market because it works fast and is very easy to use. The clarifier is ideally suitable for freshwater tanks that are up to 20-gallon in size. This fish tank water clarifier can quickly clarify water. So, you won’t have to deal with any cloudiness again for the whole week.

However, you have to use it weekly for the best results. Use UV lights to eliminate any ambiguity in the end.

It can clump any floating particles and large clusters that you can quickly get rid of with your aquarium filter. The clarifier can make the cleaning job easier for your aquarium filter too.

Keep this in mind: you will have to change at least 25 percent of your aquarium water for the ultimate results. In the end, you will restore the ecosystem of your fish tank 100 percent.

You won’t have to use any other chemical or cleaner to get the results. Now you can enjoy your fish tank crystal clear.


This water clarifier for aquariums works in freshwater tanks and is excellent for easy application. For the best results, you will have to turn on those UV lights as well. And your water will be as clean as if you have changed it right now.

2. Kloudway Aquarium Water Clarifier


  • Quick action water clarifier.
  • Clumps any floating particles.
  • Safe to use with a variety of fish and other invertebrates.
  • Suitable for use in new tanks as well.
  • Needs to be used every five days.


  • Ph level in water lowers significantly, so use carefully.


This is another one of the aquarium water clarifiers that you can trust for clearing cloudy water in your fish tank. Ensure that you are using it in a freshwater tank because it cannot work with saltwater fish tanks. The fast-acting formula used to develop this water clarifier works efficiently. It clumps all the floating particles to clear out. Therefore, when you use this water clarifier, make sure your aquarium filter is turned on.

You will have to leave it for 12 hours to see the results after using it. This might seem slow, but you will be amazed to see the effects it can produce. But you will have to be a bit careful because it tends to increase pH levels in your water. This might kill the more fragile fish in your tank to show some adverse effects or even die. Therefore, use this aquarium clarifier only after testing your water with a pH level testing kit.

Use the water clarifier in small quantities to make sure everything is working according to the plan. You will also have to change at least 25% of the water every five days for the best results. But it does a fine job when it comes to clearing the water as if you have changed it right now.


We recommend using this product with a pH level testing kit to ensure the best results. You can use this formula in small quantities to keep your fish safe. Also, keep the filtration system on. And you will have a pleasant and clear fish tank at the end of the day.

3. Acurel Aquarium Water Clarifier


  • Treats large quantities of water with a small fluid amount.
  • Works with green, cloudy, or polluted waters.
  • 100% organic formula safe for plants and fish.
  • Suitable for fish of all age ranges.
  • Quickly clear the water.


  • It might clog your filter canister.


This clarifier for aquarium water is suitable for large fish tanks that come with powerful water filters. The 10.5 oz bottle can quickly treat up to 1650 gallons of water. Therefore, you should go for this clarifier if you have large tanks of fresh water.

The use of 100 percent organic ingredients is one of the best features of using this fluid. They are not harmful to your fish and the plants you have in your aquarium. It means you can safely use this clarifier in your tank.

But be sure not to use too much of it as it will clog your aquarium filter. You might also see a reddish-brown powdery coat on the gravel present at the bottom of your tank.

However, this aquarium water clarifier works well even for green waters. Most of the aquarium water clarifiers don’t work relatively well. You will have to use it daily for the best results. If you see reddish-brown powder in your tank, slow it down and use the clarifier every other day.


This is a potent formula, and you can conveniently use it in small quantities to quickly treat large tanks. It is 100% organic and is not harmful to your fish. Just make sure you don’t use too much. You might end up clogging your aquarium filter unless you have potent equipment installed.

4. Fritz Aquarium Water Clarifier


  • Clarifies water within six hours.
  • Clumps all the particles together in large lumps for the filter.
  • Significantly improves filter efficiency.
  • Suitable for both salt and freshwater tanks.
  • Suitable for plants, reefs, and fish.
  • The formula is phosphate-free.


  • Not suitable to use with abnormal water parameters.


This saltwater aquarium clarifier is good to use with all fresh and saltwater tanks, provided you have normal water parameters. These parameters involve dissolved oxygen, turbidity, ORP, pH, and conductivity. If all these indicators are normal, you can conveniently use this fluid in your fish tank.

It is available in 8 and 16-ounce bottles, and it is suitable to use all life stages of your fish and plants. The formula is entirely phosphate-free. And won’t be harmful to your fish and plants as long as you follow the instructions.

This is a safe-to-use cleaner for reefs in your tank. It will significantly improve your aquarium filter’s overall efficiency, and your water will clear out quite fast. You can conveniently use it as frequently as you need it. Make sure to have a gap of 6 hours between each dose for the best results.

Using it too much can make the water toxic for your fish. You need to add one bottle cap or tablespoon of this fluid for every 100 gallons of water and see the results. The water will 4clear out, and you will find clumps at the top as the aquarium filter gets rid of it.


This product is safe for all kinds of fish, plants, and reefs. You can conveniently use it in your salt and freshwater tanks. Just check the water parameters before using it, especially in saltwater tanks, and follow the instructions carefully.

Things to Know About Water Clarifiers

You will find several brands on the market with their water clarifier for fish tanks on offer. Choosing the best one might seem a bit of a tough job if you don’t know what to look for when buying.

Here’s what you need to know!

– What’s a water clarifier, and how does it work?

Cloudy waters in your aquarium have tiny particles of dust, dirt, pollen, algae, and food.

These particles come from the things you put in your fish tank or the surrounding environments. Everything in the air can have an impact on your fish tank. Throughout the year, these environmental changes can heavily influence the water quality of your tank.

These particles are so tiny that you won’t be able to see them with a naked eye. Your aquarium water filter is not going to catch them either. If you don’t treat your fish tank in a timely fashion, the situation can worsen.

And this is where a water clarifier comes into play. This chemical works as glue to collect all the bits and pieces from your tank water. It makes larger clumps that your filter can conveniently grab. Using such fluid is less stressful because you don’t have to change the water and clean your tank manually.

– When should you use a water clarifier?

It is critical to know when you should use an aquarium water clarifier. If the tap water in your area has low quality, it will have ample dirt particles and other elements.

Apart from that, your tank will also have a buildup of all the uneaten food in it. There are dust and pollen in our environment naturally. It means the gravel in your fish tank won’t be 100 percent clean.

Using an aquarium water clarifier will put you back on track and have clear water in no time in such a scenario. Now, you also need to know when not to use an aquarium water clarifier.

First of all, you will have to be sure your tank equipment is working correctly. Moreover, suppose you are cleaning your tank regularly. In that case, you don’t need to use a water clarifier because it is not a quick fix. You might be overfeeding your fish, and with a clarifier, you will introduce a foreign substance into your tank. Excessive bacteria and algae formation also require a different treatment.

– The time it will take to clear the water

There are no hard and fast rules on how long it will take because it depends on your tank’s size and density. You have to make sure you go through all the instructions provided with the water clarifier. It will specifically mention the time frame for each dose of the clarifier.

Keep in mind your aquarium will get even cloudier before it begins to clear out. However, you don’t need to rush because a slow fix is best. After all, it would help if you used fewer doses to keep your fish alive. Just be sure not to use a chemical-based clarifier, or it will be harmful to the life in your tank.

– Adding it in your fish tank

Again, you need to go through the instructions carefully before you begin. You have to be sure that the quantity is correct. Plus, you also have to understand what kind of water you have in your tank? And what will the clarifier work with, and what will you have to do later?

You need to keep your water filter on. At times you will have to turn on the UV lights for the best results. The fluid you will use should be like a freshwater or saltwater clarifier.

Also, make sure the clarifier you are going for is not harmful to your fish. Double-check that you are not using too much of it in your tank. Make sure you go for natural or organic water clarifiers.

You also need to be patient because there is no test available on how much time it will take. But be sure to choose your time to use the clarifier and wait for at least 48 hours after the use.

– What if it’s still cloudy?

No clarifier will work within an hour. The clarifier you are using will mention clearly how long it will take.

After that, you will have to clean your aquarium filter and vacuum the tank gravel. Allow your fish to settle down. Your filter will collect up the clumps of particles your clarifier has gathered. And all of them should be in your filter. So you will have to clean it thoroughly.
If you see your tank is still cloudy, see the clarifier’s instructions when you can give its second dose.


Why does it get so cloudy when I use the water clarifier?

As you have given your tank a water clarifier dose, things become more evident to the eye. You can also see the clumps of particles that the clarifier has gathered. It means your product is working. The more particles are there, the more time it will take to clear.

Is fish tank clarifier harmful?

One of the primary reasons your clarifier might become harmful is overdosing. Therefore, make sure you go for the natural ingredients. Go through the instructions and see how much you must use.

The type of water you have in your tank can also affect the results, particularly in chemicals. So, make sure to go for natural ingredients when choosing a water clarifier.

It will help if you use a formula based on clarifiers used to treat drinking water. It will not change your fish tank water’s pH levels, and your fish will remain safe.

How often can I use a water clarifier in the aquarium?

You can use a water clarifier every 24 hours. However, it’s recommended to use when you see cloudy water in your fish tank. Sometimes, it may take more than 48 hours to clear the water.

Can I use a water clarifier in my fishbowl?

You can only use it in your fishbowl if it has a proper mechanical filtration system. Most of the fishbowls available on the market don’t have such a system. So, you need to manually clean the fishbowl, renew the water, and find out the cause of cloudiness.

It will usually be overfeeding. Using a water clarifier in such a small container can be harmful to your fish. So, it would help if you were careful before taking such steps.


There you have it. We have reviewed the best fish tank clarifiers for you. The best aquarium water clarifier you can go for is the API Aquarium Water Clarifier. It does its job fast, and you’ll only need to use it once a week. Just make sure you are running the filtration system when introducing this product in your tank.

It will produce even better results if you use UV lights afterward. This light will eliminate any remaining residues. It will also provide clean water for your plants and fish.


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