Cloudy water is a problem that many aquarists face, especially those new to the fishkeeping hobby. The best way to fix it and how to get crystal clear aquarium water instead depends on its source. The most common causes of cloudy aquarium water are bacterial blooms, algae, unwashed gravel, overfeeding fish, or a lack of water changes.
To get crystal clear aquarium water, there are a variety things you can do. Activated carbon, aquarium water clarifiers, regular water changes and cleaning the substrate and all help fix a cloudy fish tank.
If you’d like to learn more about how to get crystal clear fish tank water, our guide will go over the best ways to maintain it and a few removal methods of cloudy water.
How To Get Crystal Clear Aquarium Water – 3 Fast & Easy Methods
Cloudy aquarium water can be a symptom of several factors, including dirty substrate, algae growth, and bacterial blooms. It’s important to identify the cause of your murky fish tank water so you can find the best way to eliminate it.
There are a few ways to get crystal clear aquarium water, which we’ll be going over below. However, if you’re more of a visual learner, this video also does a great job explaining how to get crystal clear aquarium water:
Before you can fix cloudy water in a fish tank, there are some supplies you’ll need to get the job done.
- Aquarium water clarifier
- Activated carbon
- Filter media bags
- Gravel vacuum cleaner
- Aquarium bacteria supplement (optional)
- Algae scraper
- Aquarium UV sterilizer (optional)
If your cloudy water is caused by dirty substrate or particles in the water, this method is the most effective way of getting crystal clear water.
Turn off your tank equipment like your lights, filter, heater, and air pump before you perform maintenance on your tank. This will prevent them from becoming damaged when you lower the water level in your tank.
Using a gravel vacuum, clean the substrate to remove excess waste, uneaten food, decaying plant matter, and other debris. Make sure you move your plants and decorations out of the way so you can suck up any dirt that is underneath them.
Only move onto a new patch of the substrate when the water being sucked up by the vacuum head is clear. Clean the gravel in horizontal rows, similar to mowing a lawn.
Clean your filter and remove any gunk that may be clogging the impeller. You should also clean your filter media by gently soaking and squeezing it in some old tank water. Don’t use tap water as it will kill your beneficial bacteria!
Chemical filtration is great for keeping your fish tank crystal clear in the long run. Add some activated carbon to your filter. Make sure you place it in filter media bags if using granules. Alternatively, you can buy it as filter cartridges for your specific brand of filter.
Wash the activated carbon under dechlorinated water or some fish tank water to remove excess dust. Then, place it in your filter after your mechanical filtration.
Once you’ve finished cleaning your gravel and filter, the remaining water in your tank will likely look very polluted. Perform up to a 50% water change to improve its clarity – don’t forget to add water conditioner to the new water!
Add a water clarifier like API ACCU-CLEAR to bind the floating particles in your water so they can be easily filtered out by your filter.
If your milky water is simply due to unwashed gravel, this is the best way to clear up your water.
Using your hands or a jug, scoop up your aquarium gravel and place it into a bucket.
Rinse the gravel under running water to wash away debris, dust, and dirt. You may need to do this a few times.
Bear in mind that washing new gravel is best done when you first purchase it but don’t worry if you’ve already added it to your tank.
Empty the dirty water from the bucket and deposit the washed gravel back into your aquarium. Perform up to a 50% water change to get crystal clear aquarium water.
It may also be worth adding an aquarium bacteria supplement as washing the gravel and performing a large water change can reduce the amount of beneficial bacteria in your tank.
Cloudy green water is likely caused by algae, so you’ll need to remove it using this method.
If there is visible algae on your tank glass, remove it using an algae scraper. A straight razor blade will also do the trick. You should also clear away any algae growth on your plants and decorations with a sponge.
Bear in mind that stainless steel blades will scratch acrylic tanks, so only use them for glass fish tanks. Plastic blades are a better option for acrylic fish tanks.
An algae bloom is usually caused by too much light, so it’s best to reduce the amount of light your setup is receiving. Make sure your aquarium is positioned away from direct light like a window and only leave the aquarium lights on for 8 to 12 hours a day.
Add fast-growing live plants to outcompete the algae for nutrients. Hornwort, duckweed, Amazon swords, dwarf sagittaria, and water wisteria are some great choices.
Use a UV sterilizer to kill free-floating algae blooms and other microorganisms. This device works by penetrating the algae with ultraviolet radiation to damage it and stop it from reproducing.
It’s important to note that UV sterilizers are only effective at eliminating free-floating algae. They do not work on non-floating algae like string algae.
How To Maintain & Keep Aquarium Water Crystal Clear For A Long Time
Cloudy water can reappear if you don’t put in steps to maintain your water clarity, so it’s important to upkeep your aquarium. Although using a filter on your tank will make it easier to maintain crystal clear tank water, it can also be done without one.
Maintaining Crystal Clear Water With A Filter
Two of the best ways to maintain clear aquarium water with a filter are by using three-stage filtration and cleaning your filter regularly. Mechanical, biological, and chemical filtration make up three-stage filtration.
Mechanical filtration involves the removal of organic waste products, debris, and particulates. This is achieved with a sponge/fibrous material like fine filter floss or dense sponge filter media.
The material will then need to be squeezed out around once a month to remove the trapped waste products.
In addition, you’ll need to clean out your filter system every month to keep it running smoothly. Dissemble your filter, check for signs and damage, and remove any waste buildup from the intake tube and impeller.
Biological filter media is the conversion of ammonia and nitrite into nitrate. Both ammonia and nitrite are toxic substances to aquatic life, but nitrate is much less harmful. Nitrifying bacteria, which are housed in your filter system, are responsible for this process.
Lastly, chemical media filtration is the absorption of phenols (bad odors), discoloration, and dissolved particulates using porous materials like activated carbon. However, activated charcoal will eventually become oversaturated and need to be replaced every two to four weeks.
Using all stages of filtration and a powerful filter will help you achieve and maintain crystal clear water.
Maintaining Crystal Clear Water Without A Filter
Although using a filter is ideal for keeping your tank healthy and clean, there are other ways to improve the clarity of your water. Live plants, driftwood, and Indian almond leaves are beneficial for this purpose.
Live plants have a multitude of advantages in a fish tank. They increase oxygen levels during the day, help absorb toxins, reduce algae blooms, and provide hiding spots for aquatic life.
Driftwood releases tannins into your water, which slightly increases the acidity in your tank.
This helps boost the immune system of your tank inhabitants by repelling viruses and bacteria. It also offers shelter for your fish tank inhabitants.
Indian almond leaves also leach tannins that have antifungal and antibacterial properties. In addition, they can lower pH levels, reduce stress levels in fish, and boost the immune system of your fish.
If you don’t have a filter in your aquarium, adding live plants, driftwood, and Indian almond leaves to your fish tank is ideal for improving water clarity. They will also enhance your water quality to keep your fish healthy.
However, you’ll still need to perform frequent water changes to keep your aquarium water clean and stable. A weekly water change (removing around 10% to 15% of water) is usually sufficient.
How To Prevent Aquarium Water From Getting Cloudy
Cloudy water can be a real nuisance as an aquarium owner, but there are many ways you can stop it from happening in the first place.
Following all of the below methods will help you keep your fish tank water crystal and improve the quality of your water. It will also promote a much healthier habitat for your fish!
Perform Frequent Water Changes
Regular water changes are important not just for increasing the clarity of your water, but also for the health of your aquarium. They prevent fluctuations in water parameters and ammonia spikes.
An ammonia spike can be dangerous to your fish as this compound is lethal, even in small quantities.
Most fishkeepers perform weekly partial changes (around 10% to 15%), though the bioload and volume of your aquarium will need to be factored in. A small, overstocked tank will benefit from larger and more often water changes.
Regularly Clean Your Filter
It’s easy to forget to clean your filter, but this is a crucial job that you shouldn’t slack on. Over time, fish waste, decaying plant matter, uneaten food, and other debris will build up in your tank water filter.
You’ll need to remove this gunk around once a month to keep your filter operating efficiently. Wipe away the grime from inside your filter, including the intake tube and impeller. You should also squeeze out your filter bag to dislodge trapped waste.
Never use tap water to clean your filter as it will kill your beneficial bacteria. Only use your tank’s water.
Don’t Overfeed Your Fish
Feeding your fish too much will contribute to murky water, among other issues like algae and poor water quality. It will also result in your fish producing more waste.
All the uneaten food and fish poop will fall to the bottom of the substrate, which can lead to unwanted bacteria blooms and an ammonia spike if it is not removed.
You should only feed your fish as much food as they can eat within two minutes. After this time, remove excess food with a net. Most fish species benefit from two meals a day, though some aquarium owners fast their fish once a week to improve digestion health.
Vacuum The Substrate
While regular water changes will stop cloudy water to some degree, you’ll see better results if you also vacuum your substrate. Doing so will remove fish waste, leftover food, rotten plant matter, and fine particles that aren’t picked up by your water filter.
You should aim to clean your substrate twice a month, though tanks with high bioloads or messy fish may need to be cleaned more frequently.
Don’t Overstock Your Aquarium
As tempting as it is to fill your tank with lots of different species, you need to be careful not to overstock it. An overcrowded aquarium can cause many issues, including excess waste, decreased oxygen levels, high ammonia levels, and stress.
Use the “one inch of fish per gallon” rule to help you calculate the number of fish you can house in your aquarium.
Cycle Your Tank Properly
Every aquarium needs to go through the nitrogen cycle before it can safely house fish. The nitrogen cycle is the natural process of converting nitrogenous wastes into less harmful substances. This is carried out by nitrifying bacteria.
Cycling an aquarium can take four to eight weeks. You’ll need to add an ammonia source like fish flakes, raw shrimp, or pure ammonia to the tank to start the nitrogen cycle.
You’ll also need to test your water frequently with an aquarium testing kit to monitor your ammonia, nitrite, and nitrate levels. Once nitrate levels start rising and both ammonia and nitrite are zero, the nitrogen cycle is complete.
During the cycling process, it’s very common for the water to become cloudy due to a bacterial bloom. This isn’t something to be worried about and is completely normal.
Continue adding an ammonia source and checking your water parameters. The cloudiness will eventually go away on its own.
Wash New Gravel
One of the main causes of milky water in a new tank is dusty gravel. If you’re a new aquarium owner, you may not know that you’re supposed to wash new gravel before adding it to your tank.
Unwashed gravel contains a lot of dirt, dust, and debris that needs to be removed, otherwise, it will cloud up your water. Rinse the new substrate under running tap water to remove all the impurities, then place it in your tank.
Add Live Plants
Using live plants in your aquarium is ideal for keeping your tank clean and crystal clear. They also provide many other advantages to your aquatic pets by increasing oxygen levels, absorbing carbon dioxide, preventing green water or algae, and removing toxins.
Aquatic plants offer natural filtration, so they can be a real asset to a freshwater or saltwater aquarium. They also work wonders in setups without filters.
Use Activated Carbon
Activated carbon excels at preventing cloudy water as it removes dissolved contaminants. This includes phenols, tannins, chloramine, and chlorine. Using chemical filters adds a deeper layer of polish to your water to keep it sparkling clear.
Your chemical filter medium should be placed after your mechanical filter medium (usually filter floss or sponge filter material). You’ll need to replace it every two to four weeks as it will eventually become oversaturated.
Use Aquarium Water Clarifiers
Water clarifiers can be a great help to new aquarium owners who regularly deal with milky water. However, they can also be worth using in an established tank to maintain clear water.
These products bind bigger particles in your tank water into tiny particles so your filter can pick them up more easily.
How Long Does It Take For Cloudy Aquarium Water To Get Crystal Clear?
The length of time it takes for cloudy water to clear depends on its source and your removal method. In most cases, it will take a day or two for your water to improve.
However, it can take up to a week before you see any noticeable results, especially if your milky water is caused by a bacterial bloom.
Bacterial blooms are common in new tanks that haven’t undergone the nitrogen cycle yet. When there are too many nutrients in a tank and an inadequate supply of nitrifying bacteria to combat it, the good bacteria will try to combat this by populating quickly.
This bacterial bloom can make your water look very murky – like someone has emptied a glass of milk into it. It can take several weeks for the water to clear.
Although it’s tempting to fix this problem with a water change or water clarifier, the best solution is to simply wait it out. The cloudiness will disappear eventually.
Changing the water or other removal methods will only temporarily reduce your tank’s murkiness. It will make the bacterial bloom last for a longer period as you’ll be removing some of the beneficial bacteria.
Will Cloudy Water Hurt My Fish?
Cloudy water itself won’t hurt your fish, but its presence can indicate a problem with your aquarium. For instance, if you’ve only just set up your aquarium, murky water is a sign of a bloom in bacteria and that your setup hasn’t finished cycling yet.
Adding aquatic life at this stage is unwise as it will likely lead to elevated ammonia levels due to a lack of nitrifying bacteria in your water.
Alternatively, milky water can be a side effect of giving your tank inhabitants too much fish food. This can lead to health issues like swim bladder disorder, improper digestion, and a fatty liver. It can also cause ammonia levels to skyrocket.
If you’re dealing with green water that looks like pea soup, algae is likely to be the culprit. Algae blooms are the result of too much light and excess nutrients in the water. High phosphate levels from overfeeding aquatic life and a lack of tank maintenance can contribute to algae.
Although algae isn’t dangerous to aquatic life, it often means that your tank is not as healthy as it could be.
How Long Can Fish Live In Cloudy Water?
The length of time fish can survive in cloudy water greatly depends on its cause. Green water caused by algae or milky water due to poor husbandry can be hazardous if it’s not dealt with.
If the problem isn’t resolved, your tank inhabitants will likely become sick and pass away in a matter of weeks.
However, milky water as a result of unwashed new gravel won’t have any negative effects on your aquatic pets other than making the tank look murky. The cloudiness in this case is simply due to excess dust.
Cloudy or murky water in your aquarium can be unsightly, but it’s usually very easy to fix no matter the cause. Activated charcoal, aquarium water clarifiers, cleaning the substrate, and proper tank maintenance will help you get crystal clear water.
However, it’s also important to resolve the cause of your dirty water, otherwise, it won’t stay clear for very long. Overfeeding your aquarium inhabitants, a bacterial bloom, algae, or unclean substrate can cause your aquarium to look murky.
You’ll need to fix these problems with the appropriate solutions mentioned earlier in this article to maintain clear water in your aquarium.
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