A healthy, clean, and balanced aquarium provides a conducive and comfortable environment that is ideal for optimal growth and normal functioning of freshwater fish, dwarf shrimp, and other inhabitants. However, the cloudiness of the aquarium water is a strong deterrent. It messes with the water quality and clarity by making the tank water murky.
Cloudy or hazy white aquarium water is brought about by issues resulting from the residue of poorly cleaned aquarium substrate, dissolved substances, dirty filter media, and lastly, bacterial blooms which are usually common in new tanks.
These factors prompt cloudy white aquarium water by enabling the build up of unwanted materials and toxic compounds, and if the aquarium filter is not efficient to handle them, it will ultimately result in a cloudy water situation.
Now, let’s take a look at the common causes and effective solutions for resolving cloudy white water in fish tanks.
Causes of Cloudy White Aquarium Water
Cloudy white aquarium water occurs due to a number of reasons which include and are not limited to the following:
1. Substrate Residue
It is common knowledge that aquarium substrate (especially gravel and sand) needs to be adequately washed before adding it to the bottom of your aquarium. This aids in getting rid of tiny particles of dirt and dust capable of dissolving and ruining the clarity of aquarium water.
In a situation where the tank water turns cloudy instantly or shortly after filling the tank, there is a very high chance that the substrate was not properly washed or in some cases— not washed at all.
Solution: At this point, you need to siphon the substrate and/or drain the tank.
When I was a beginner, I tried sand without rinsing it first. Well, it was a mistake. The tank turned into a cloudy mess that refused to settle to the bottom of the tank. Siphoning did not help because it was way too dirty. Eventually, I had to tear it down and restart the tank.
You can also read my article “How to Change the Substrate in the Tank”.
2. Dissolved Constituents
Dirty or improperly washed aquarium substrate is not the sole cause of the cloudiness of water in fish tanks. Another possible reason for this disturbing condition is the presence of dissolved constituents in the water. For example, silicates, phosphates, and heavy metals which are capable of making the tank water cloudy, hence ruining its quality.
These substances are found in both water and substrates and they also contribute to the proliferation of algae.
To troubleshoot this problem; first, you need to test the water using a pH kit.
An aquarium with a high concentration of mineral content will most likely have a high PH — signifying alkalinity.
Solution: Next, treat the water with a good water conditioner (for example, Seachem Prime – link to check the price on Amazon), thus making the water safe for fish and inverts.
An alternative to a water conditioner is to use Reverse Osmosis (RO) water. This can be also sourced from a local fish store if you do not have RO/DI system in your home. RO water will help in resolving cloudy tank water, balancing the pH (you have to use mineralizers for that), in addition to other benefits.
3. Bacterial Blooms
If your aquarium has a strong milky or foggy appearance, then it is a clear indication of a bacterial bloom.
The build-up of ammonia and other toxic compounds in a newly set-up aquarium that is undergoing cycling is termed “new tank syndrome”.
This phenomenon normally surfaces some days or weeks after setting up an aquarium, and due to the fact that it takes several weeks to form beneficial bacteria that can clear nitrogenous compounds from the aquarium water— the cloudy white water formed by waste and harmful compounds will take a while to clear completely.
Additionally, milky or cloudy aquarium water may also be caused by unfiltered food and plant residue within the period of cycling.
Solution: To facilitate the clearing of cloudy water; make sure to perform water changes, vacuum the substrate and test the water regularly to measure the ammonia and nitrites levels— to know if they are converting to nitrates, then give it some time to settle and clear.
Moreover, you can add a piece of filter wool to your filter. It works by trapping particles of debris that are in the aquarium column.
Additionally, flocculants can be used to clear cloudy water. It makes the debris or bacteria causing the cloudiness to clump together thereby making it easier for the filter to take them out of the water.
How to Remedy Cloudy White Aquarium Water
Having looked at the common causes of cloudy white aquarium water, we can summarize here some possible solutions to this rampant water clarity problem:
1. Maintenance of the aquarium filter:
It is essential to clean the filter and its components during routine maintenance of the tank as this promotes its efficiency and keeps it in good working condition.
In addition, you should add a filter wool or activated carbon media to your aquarium filter. It will help absorb free-floating particles and debris that make the aquarium water cloudy.
Furthermore, ensure that the filter is adequate for your tank size and powerful enough to eliminate debris, waste, and harmful toxins from your aquarium.
Moreover, a clogged filter media does a terrible job at filtration. Therefore, there is a need to clean the filter pads regularly to encourage optimum performance of the filter, or else the issue of cloudy aquarium water will linger on.
Make sure to clean the filter pads/media in a clean, dechlorinated freshwater as normal tap water may kill the beneficial bacteria already attached to the surfaces. Another option is to use the old tank water after water changes.
2. Water changes
Regular water changes is a necessity as it aids the elimination of harmful/toxic compounds caused by large quantities of fish waste, uneaten food, accumulated detritus, and decaying plant matter.
Weekly partial water changes in synergy with mechanical filtration will greatly assist in keeping the tank water clean and clear of impurities.
Avoid changing more than one-third of the tank water at a time as it will cause a massive change in the water chemistry and some fish species may not be able to handle the drastic swings, a 25% water change is good enough.
If you are a shrimp keeper, be very careful with massive water changes. Dwarf shrimp don’t like changes at all. It is not recommended to do more than 10% of water change at once. There are multiple reports that big water changes cause molting problems (The White ring of death).
3. Use flocculants
These are usually marketed as water clarifiers and they are good at sticking floating particles of debris together, hence making it sizeable enough to be trapped by the aquarium filter.
Water clarifiers may help improve the clarity of the tank water by getting rid of the cloudiness, however, they may not combat the main cause of the condition outrightly.
In addition, you need to make sure that the water clarifier is safe for your fish, live plants, and inverts before its application.
Moreover, keep in mind that some water clarifiers will alter the color of the aquarium water; turning it blue, orange, etc. depending on the color of the clarifier.
Also, clarifiers can be detrimental since they are capable of changing the water chemistry and such changes might hurt your fish, so you are advised to use with caution.
For example (links to Amazon):
– API ACCU-CLEAR Freshwater Aquarium Water Clarifier,
– Tetra WaterClarifier Treatment Solution for Freshwater Aquariums
4. Proper cleaning of the substrate
Cleaning/washing of the aquarium gravel before its addition to your tank will eliminate little particles of dirt that can cloud the water.
Pour the substrate into a large container and run cool water over it, use your hand to wash it until the water in the container runs clear, once this is done you can now add the substrate to your tank.
Aside that, you should use an aquarium vacuum to siphon dirt and debris from the substrate, this aquarium care activity should be done regularly in fish tanks.
How to Prepare Gravel for a Tank
- Place a sieve, over the bucket, and fill it half full of gravel.
- Start pouring water over the gravel in the sieve, while gently shaking it. Do it until the water runs clear and you are satisfied with the result.
- Place the gravel into the bucket.
- Fill the bucket with tap water. The water should completely cover the gravel.
- Stir and move the gravel around (use a stick if necessary).
- Leave it in the bucket for 5 – 10 minutes. It will soften up any dust and debris that may be on the gravel.
How to Prepare Sand for a Tank
The rinsing process to clean sand is really easy.
- First, you take your sand and sieve it into a bucket.
- Next, fill the bucket with water. Go ahead and pour out the water. The water should start out cloudy and gradually become cleaner as you continue to rinse the sand.
- Be careful not to lose your sand during the rinsing process.
- Repeat the process by adding and dumping water until the water starts running out clear.
- Important: When you think that sand is absolutely clean – rinse it again!
Depending on how much sand you have, it usually takes from 15 minutes to 1 hour.
How to Prepare Soil for a Tank
- Place the soil into the buckets.
- Fill the buckets with tap water. The water should completely cover the soil.
- Rinse it in the buckets. Stir in very vigorously! Ideally, you need to do it at least 2 times a day because ammonia concentrates in the lowest section of the substrate.
5. Adherence to stocking limits and proper feeding habits
Excess waste from multiple fish and uneaten food are sure to ruin the water quality as these breakdown into harmful toxins easily, thereby leading to bacterial blooms that can prompt cloudy white water in your tank.
Overstocking leads to several issues (aggression, diseases, etc.) and it is capable of deteriorating an environment, hence making it toxic and unhealthy for aquatic life.
It is best to cut back feeding of aquarium fish to just once a day or every other day to significantly reduce food decays and the build up of ammonia which can pollute the tank.
Keep in mind that overstocking and overfeeding of fish will promote excess waste which translates to more nitrates, cloudiness, and likelihood of a bacterial bloom happening.
For shrimp keepers I would recommend checking my articles:
Cloudy tank water in fish tanks is a problem every aquarium owner encounters at some point, most especially when starting out.
In order to forestall the occurrence of cloudy water, be sure to keep the tank clean— carry out partial water changes, clean the aquarium gravel and filter properly, and always test the tank water to ensure that ammonia, nitrites, and nitrates are all at the recommended levels.
Finally, it is worth mentioning that you are less likely to encounter cloudy water problems in a clean and well-maintained aquarium.