Quick Update for 2019: We recommend Seachem Prime as the best water conditioner for both fresh and saltwater. Being one the bestsellers on Amazon, the prime helps remove chlorine, chloramine & detoxifies ammonia, nitrite and nitrate.
This product is consistently reviewed as the best fish tank water clarifier available, giving you clear water in a matter of hours. Instead of a liquid, it comes in packets that you add to the filter of your tank, making it safer for your fish and very effective. A package of 6 packets can clear up to 330 gallons. It works to condense both organic and inorganic pollutants, as well as improve the chemical, biological, and nutrient balance of the water. Algone also claims to increase the level of dissolved oxygen — allowing your fish to breathe better — and stimulate microbial activity in your aquarium to prevent future instances of cloudy water. Many customers seem satisfied with these claims so the higher price — almost 3 times that of the next product on the list, Aqueon — appears to be worth it. It is safe to use in both fresh and saltwater tanks, as well as with all types of fish, plants, snails, algae eaters, coral, polyps, live rock, invertebrates, and whatever else you might have in your tank.
works on both fresh and saltwater tanks
many benefits other than simply clearing the water
This could easily be chosen as the best aquarium water clarifier since it is highly effective and one of the more affordable versions of this product on the market. It is safe for all types of freshwater fish and plants and works quickly, taking less than 6 hours to clear a 37 gallon tank. Reviewers have used this product in tanks with and without filters since it causes minuscule particles to clump together and sink to the bottom. If you do not have a filter, make sure to use a gravel vacuum to clear the clumps from the bottom of the tank, or the problem will return with a vengeance. Aqueon products are made with the user in mind and come with clear instructions answering any questions you might have, as well as useful dosage aids — this product has a clearly marked dosage cap to keep you worry-free.
freshwater tanks only
with larger tanks it tends to take longer to clear than other brands
Customers love this brand for its efficacy and versatility. It works for both fresh and saltwater tanks and is plant and reef safe. Some reviewers say that it took 6-12 hours to clear, but the better you maintain your tank, the less time it should take to clear in the event of clouding (with reviewers citing less than 3 hours on the second use). It works best when used in combination with a powerful filter.
Acurel has been serving many satisfied customers for 45+ years. This water clarifier can only be used with freshwater tanks, and it is made using organic extracts from renewable resources. Fast working, it will clear the water in your tank within hours and can also be used as a preventative method to ensure clear water all the time since it will not eliminate beneficial bacteria in your tank. However, make sure not to use this product with saltwater or brackish water species!
Tetra is a well-trusted brand by aquarium-owners, and for good reason. They produce every type of product you could need to maintain a healthy environment for your aquatic pets. This water clarifier is state-of-the-art: it is phosphate free, it won’t affect pH levels so it will allow you to maintain levels of beneficial bacteria, and it will leave you with crystal clear water. It is safe for all varieties of fish and other species in your freshwater tank. However, users report a longer time until seeing clear water. Many people say they needed to use 2 doses before their water fully cleared, inserting a second dose 24 hours after the first and seeing clear water in about 48 hours. It might be worth the wait, though, since it is one of the cheapest water clarifiers available and currently the cheapest product on this list!
won’t affect pH levels
takes longer to work and might require 2 doses for full efficacy
This product used to be ranked as the best fish tank water clarifier on the market for many years due to its affordable price and great marketing. However, some users have found that it kills their fish, even when they use the recommended amounts. Reviews vary, and many people are still very satisfied with this product, so it is included in this list because of its longevity in the marketplace. It can only be used in freshwater tanks and works for a variety of causes of cloudy water. It works best if used with a filter, and can take a bit longer to fully clear the cloud — 24-36 hours. However, despite the wait, users report clearer water in the end when using this as compared to other products.
Kent has created a product-line using unique combinations of ingredients to ensure the best care for your aquatic pets. Their water clarifier offers versions to clear both fresh and saltwater tanks. Its pH balanced formula contains no nitrates or phosphates, and is safe for many varieties of aquatic species, including corals, zooxanthellae, anemones, and macroalgae. However, some users have reported that it is not safe for shrimp. It is priced affordably, and right now Amazon has made it even more affordable by including it in the add-on program for only $5 for 8oz or $7 for 16oz. Users report varying times to see results, with some people saying they waited 10 days and others saying they noticed clearer water on day one. It seems that this product is most effective if used daily for at least 5 days, and then preventatively when you change the water in your tank.
safe for zooxanthellae and macroalgae
fresh and saltwater tanks
not safe for shrimp
can take up to 10 days for totally clear water
1) What does a water clarifier do?
After adding a few drops to your tank, all you have to do is wait as the substance causes small particles of pollutants clump together and either sink to the bottom of the tank or get caught by the filter. Originally, these particles were so small that your filter couldn’t grab them, so they floated in the water and caused it to be murky. Once you add the clarifier, it causes them to stick together and form larger groups enabling either a filter or gravel vacuum to remove them from the water.
2) Why does my water get cloudy?
Your water can become polluted by both organic and inorganic substances, such as leftover food, products that you have added to your water, or residue from toys you place in the water. Small particles of pollutants float in the water without being trapped by the filter, causing a cloud to form.
3) Why does my water appear cloudier after adding a water clarifier?
Once you add the clarifier, the particles in the water start to clump together and therefore become more visible. Don’t worry! This is the first sign that the product is working. The larger clumps will either be filtered out or sink to the bottom of the tank.
4) Will a water clarifier harm my fish and plants?
It shouldn’t! However, it is a good idea to make sure that all your aquatic pets are healthy before attempting to change anything about the balance of the tank. Also, some clarifiers are not safe for all species, so make sure to check the specifications.
5) How do I know if there is a problem / if I have added too much?
Watch your fish for any reaction after you add the clarifier. If they start moving erratically or look like they are gasping for oxygen, immediately begin a water change in order to reverse any possible damage the clarifier might have caused. And make sure to follow the dosage instructions on the product: less is more when it comes to aquarium products.
6) Do I need a filter in my tank to use a water clarifier?
Water clarifiers are most effective when used with a filter since it will catch as many of the particles as possible. However, clarifiers will cause some of the particle clumps to sink to the bottom of the tank, so you can effectively remove them by using a gravel vacuum.
7) Can I use any water clarifier in my saltwater tank?
No! Make sure to check the specifications of the product. Some clarifiers are effective for both fresh and saltwater tanks, however many are only safe for freshwater. Try Algone, Aqueon, or Kent Marine for your saltwater tank needs.
8) How long will it take to clear the water?
That depends on the size of your tank, the severity of the cloudiness, and the product you choose. Most products will work within hours, with some taking up to 48 hours for complete results. Products like Kent Marine Tank Clarifier are more effective when used in small doses over a longer period (up to 5 days) so it can be used as a preventative method.
9) Do I need to use any other products at the same time?
You can safely use other products (like water conditioner) at the same time as a water clarifier. Also, you will have more success with your clarifier if you use a filter in your tank, and you definitely need a gravel vacuum to make sure to remove all the particles that have sunk to the bottom of the tank.
10) How often can I use a water clarifier?
It is best to use a clarifier as a “last resort” when you have already cleaned your tank and ensured that the pH balance is appropriate for keeping a healthy aquarium environment. If murky water keeps returning, it is a sign that there are larger problems to take care of. Once you have ensured the overall health of your tank, you can use a water clarifier every time you change the water in your tank to give you more time with clear water.
11) What do I do after I add the product?
Wait for the specified amount of time while making sure that your fish still look happy. If your water is not clear by the end of the time period, check if it is safe to add another dose and try for a second round. Once your water is clear, you need to change your filter as well as sweep the bottom of your tank with a gravel cleaner to remove all the gunk that the clarifier helped to trap.
12) How do I maintain a tank with clear water?
Make sure to clean your tank regularly (at least every 2 weeks) and don’t overfeed your fish. Also, check that any toys or trinkets you buy will not leach paint or other residues into the water.
13) Can you use a water clarifier with fish in the tank?
Yes, you can leave the fish in their environment. Just make sure to observe them in case they exhibit any signs of distress.
14) Are water clarifiers safe for all types of aquatic pets?
Some are, and some aren’t. Make sure to check the label. Kent Marine Tank Clarifier is not safe for shrimp, and there have been reports that API Accu-Clear Water Clarifier has killed several varieties of fish. Also, make sure to choose the proper fresh or salt water variety to ensure it is safe for your type of aquarium.
15) When should I use a water clarifier?
When the water in your tank is cloudy and after you have addressed any other possible causes for the cloudiness. You can also use a small amount each time you clean your tank as a preventative method to keep your water clear for longer.
16) Will water clarifiers reduce levels of beneficial bacteria in the tank?
They shouldn’t since they are designed to simply cause particles to clump together for easier removal. However, you should always check the pH regularly, especially after changing the water or adding new products.
17) What other products do I need to maintain clear water in my tank?
They are created using formulas similar to those used to purify drinking water.
19) If my water is cloudy, is it safe to double the dosage?
Better not, in case the extra dosage causes stress on your fish. Just try the first dose and wait the necessary amount of time, then if your water is still not clear you can try the process again.
20) Which product should I choose?
The best aquarium water clarifier for you depends on the conditions of your tank. However, the top three options listed here are all consistently rated well and will work for both fresh and saltwater tanks, so you should be satisfied with any of those products.