Why does my freshwater tank get cloudy

Unfortunately, there is no single answer as to why your aquarium water is cloudy because there is no single cause. However, based on the color and circumstances under which cloudy water appears, it usually can be pinpointed to a couple of basic causes. If the water is cloudy immediately or within an hour or two of filling the tank, it's probably due to insufficiently washed gravel.

Drain the tank and rinse the gravel until the water runs clear. That should resolve the problem. If washing the gravel doesn't solve the problem, the next most likely cause of cloudy water in a newly filled tank is a high level of dissolved constituents, such as phosphates, silicates, or heavy metals. If you test the water, you'll likely find that the pH is high alkaline. In these cases, treating the water with conditioners will often resolve the problem.

Another option, which has many benefits beyond resolving cloudy water, is to use RO Reverse Osmosis water. Your local fish shop may sell it or sell units capable of making RO water.

Often, cloudy water doesn't appear the instant an aquarium is set up. Instead, it appears days, weeks, or even months later. The cause is usually due to bacterial bloom. As the new aquarium goes through the initial break-in cycle, it is not unusual for the water to become cloudy or at least a little hazy. It will take several weeks to several months to establish bacterial colonies that can clear waste from the water.

Over time, that cloudiness will resolve itself. If your aquarium water becomes fogged with grayish or white cloudiness the minute you fill a new tank, your problem is almost certainly caused by dust and dirt washing off the new substrate, typically gravel.

The fix for this issue is simple; just empty your tank, remove the gravel, and wash the substrate under running water until the water runs clear. If your substrate is clean, but the water is still murky, the problem is most likely due to high levels of dissolved constituents, including heavy metals, silicates, or phosphates. You can typically solve the problem by dosing the water with a tap water conditioner or pH buffer.

In some regions, it may be that the tap water is causing the issue. You can solve that problem by using Reverse Osmosis RO water instead of tap water.

Most good fish stores sell RO water, or you might prefer to buy an RO unit, which will be more cost-effective if you have a large tank or more than one setup. If you have a new tank and the water turns murky within a few days or a week or so after you set it up, the cloudiness is most likely caused by bacterial bloom. Bacterial bloom, or bacterial blossom, as the phenomenon is also known, occurs when a new biological filter system is maturing. The problem generally resolves by itself over a couple of weeks or months.

Meanwhile, you can help the beneficial bacteria in the biological filter by vacuuming the tank thoroughly at least once each week to remove fish waste, uneaten food, and plant debris.

Sometimes, reducing the amount of food that you give your fish can help to ease the burden on the filter system, clearing the water as a result. You can trigger bacterial bloom by switching off your filter system overnight.

You can use water additives called flocculates to help clear your water. Flocculates work by causing tiny particles of floating debris to clump together so that the mechanical element of your filtration system can remove them from the water, effectively curing the cloudiness. Many hobbyists inadvertently cause bacterial bloom after a big water change that upsets the delicate eco-balance within the aquarium.

Removing too much water from your tank can kickstart a mini-cycle, when the beneficial bacterial colonies that live in your tank and in the filter media begin to repopulate.

The larger the aquarium, the more waste your aquarium can handle before it becomes a problem to your fish. The reasons for this are fluctuations in the nitrogen cycle, and the release of gases in solution as the result of an increase in water temperature.

Also, be sure to monitor and change your filter cartridge on a regular basis. A good rule of thumb is at least once a month, or twice a month if you have a heavy fish load or if you have fish that produce more waste such as Goldfish or Cichlids. However, taking measures to prevent and avoid cloudy water in advance is a far better approach than attempting to eliminate it once it starts.

When you begin to see cloudy water in a new aquarium, it's best to just let it run its course. Continue reading for some additional tips. Beginning aquarists often fear their fish will starve to death, so they feed heavily and often.

Unfortunately, there are few, if any, nitrifying bacteria present to break down the resulting waste or uneaten food, which the cloudy water bacteria take advantage of and continue to multiply. Even worse, harmful ammonia and nitrite levels may begin to rise. Fish in nature don't always eat every day, and some predatory fish may only eat once or twice a week.

No fish ever starved to death in three days. More fish mean more waste and more food for the microbes causing the cloudy water. Too many fish in a new aquarium may also cause a rise in harmful ammonia and nitrites. Adding activated carbon media or activated carbon pads to the filter will help clear the water and adsorb nutrients that feed the bacteria bloom.

If you have access to another healthy, well-established fish tank, adding a few handfuls of gravel from that aquarium will seed the beneficial bacteria and speed up the clearing process. Aquatic stores sometimes keep filter cartridges, bio-sponges and wheels floating in stocked aquariums to seed them with bacteria and will send these items home with new setups to help get the biological balance going.

This has the same effect as adding gravel from an established tank. Have aquarium water tested for ammonia and nitrite as soon as the water begins to get cloudy. In most situations the levels will be zero, meaning there is no cause for concern. We understand that seeing cloudy water in a new aquarium, can be alarming.