Most aquarists understand the lethal effects of ammonia and nitrite but are unaware of safe nitrate levels in aquarium water.
Too much nitrate is harmful for your fish and other tank inhabitants, so make sure to keep your nitrate levels low. Regular water changes are important to keep nitrates and nitrite levels down in an aquarium. This guide is full of valuable information about how to lower nitrates in your aquarium.
Monitoring the nitrite level is an important part of nitrogen cycle.
Nitrogen cycle
A well-run nitrogen cycle is the basis of a properly functioning aquarium. Let me recall once again how the nitrite peak is formed.
Ammonium ions are formed during the decomposition of plant and food residues, fish feces and other organic matter in the fish tank.
Ammonium ions are not poisonous by themselves. However, when ammonia is formed, it becomes toxic to aquarium inhabitants. Toxic ammonia is formed if the pH scale rises above 7.
Bacteria (mainly Nitromonas) in a properly stabilized fish tank convert both, ammonium and ammonia, to nitrites.
These bacteria settle very quickly in new tanks, improving the decomposition of ammonia and ammonium.
This is followed by the conversion of nitrites (mainly by Nitrobacter bacteria) into nitrates, which is a source of nitrogen for plants.
Nitrites-degrading bacteria need time to develop in newly established aquariums. It is at this time that nitrite peaks.
This is because there are still too few filter bacteria in the aquarium to convert the increasing nitrite content into nitrates.
Nitrite peak
After a certain period of time, a sufficient number of nitrifying bacteria will be formed in the fish tank. This results in nitrite reduction, which leads to the termination of the nitrite peak.
So when might the peak in nitrites occur?
- During the starter phase of the aquarium, which is due to the lack of a sufficient number of bacteria converting nitrites to nitrates (usually between the 5th and 15th day)
- After disease treatment – medicines for fish disease are usually harmful to filter bacteria.
- After replacing the filter or as a result of too intensive cleaning of the filter media (such a procedure removes a significant part of beneficial bacteria).
When you set up an aquarium, be sure to monitor ammonium and nitrate levels. Fish should only be allowed into the tank when the level of these compounds is close to zero. At this time, you should stock up on appropriate aquarium tests. The drop test will be the best and most accurate in this case.
Attention!!!
The fact that after 2 weeks nitrite and ammonium levels are close to zero does not mean that the aquarium is already cycled. Improper bacterial growth medium can start late decomposition. If we test the ammonium and nitrite levels after 10 days and find that the results are close to 0, it may mean that the aquarium has not started cycle yet.
It is worthwhile to test the levels of these compounds every few days since the fish tank was set up. Keep in mind that each fish tank cycles differently. Patience is key in this process.
Biological balance
When do we know that our fish tank is already in biological balance?
- We will observe the healthy growth, appearance and behavior of animals in the aquarium, according to the characteristics attributed to the species,
- Plants will have a healthy appearance consistent with the characteristics assigned to a given species,
- The level of algae in the aquarium is maintained in an amount that does not pose a threat to other organisms and does not adversely affect the aesthetic impression,
- The aquarium maintains stable water parameters, such as pH, hardness, concentration of nitrogen compounds.
It is important to realize that the biological balance can easily be disrupted. Even trivial factors, such as the introduction of new fish to the aquarium, plants, changes in filtration or lighting intensity can affect the biological balance. The imbalance can be evidenced primarily by a rapid and invasive algal bloom that poses a threat to animals and plants, thus destroying the aesthetic effect of the aquarium.
An imbalance in the aquarium can also be indicated by symptoms:
- Cloudy water (white color), which is associated with protozoan blooms,
- Disturbing behavior of fish, inconsistent with the characteristics of individual species,
- Fish deaths,
- Poor plant growth or stagnation,
- A rot odor or hydrogen sulfide smell above the aquarium
Whether you’re buying fish, or your aquarium is already stocked with healthy fish, you should know how to check nitrate levels.
Newly established fish tank has almost no suitable bacterial flora. This may involve difficulties in maintaining the cycle. Improper nitrogen circulation can inhibit the growth of your plants.
No matter how carefully you maintain your fish tank, there’s always a certain amount of nitrate levels present in the water. Tap water in many areas of the US contains high levels of nitrate, but it’s not harmful. It does vary based on where you live. If you have any doubts, contact your local water treatment plant to check the nitrates levels.
The average U.S. tap water contains nitrate levels of more than 10 ppm. To reduce nitrate levels in your tank,a look for another source of nitrate-free water. Nitrate is also found in rainwater, which makes it perfect for plants in the garden, but is a bad thing for fish and other water living creatures in an aquarium.
Fish tanks are usually full of nitrates because they’re created by decaying organic matter and detritus, as well as the decomposition of fish food and waste. If your filter media isn’t maintained, bacteria inside the media will grow in number, creating excess ammonia. Nitrates are often found naturally in water. High levels of nitrate can cause problems for your plants and fish.
Freshwater aquariums should have a nitrate level of 25-50 ppm. The lower the level of nitrates, the better. As a beginner, it is best to try to keep the nitrate level below 10 parts per million (ppm). Your aquarium should be tested monthly for nitrate concentration.
How should you test for nitrates?
Your aquarium should be tested monthly for nitrate concentration. When your tank is new, you need to test the water regularly to make sure you’ve got the right levels of nitrates, ammonia and other nutrients. Always have your test kit handy to make sure you’re on track. Fish stores usually have a good understanding of their water quality. Ask them what it costs to test your water, or if they can provide you with an analysis. Sometimes stores will test your water for free, or charge a nominal monthly fee that usually works out better than buying test kits.
Paper Strip Tests
If you need to buy testing kits you can do better buying the individual test kits for the specific things you want tested, as it will usually be cheaper than buying a master test kit. You can also buy all-in-one master test kits, which usually include tests for water pH and hardness levels, as well as for ammonia, nitrites, and nitrates.
If you need a quick water test, paper strip tests are great. They’re easy to use and very inexpensive to buy.
You drop one of the paper test strips into the sample of tank water and wait for the results.
After a few minutes check the color of the strip with the color chart that’s included in the test kit. The strip color lets you know approximately how much nitrate is in your water.
Liquid tests
Liquid test kits generally work better than paper strips for hobbyists, because they are often considered to be more accurate. The kit includes a small test tube, a pipette, a vial of a liquid testing medium, and a color chart.
You add a little aquarium water to a tube, then a few drops of testing fluid, shake it up and wait a few minutes for the results.
Be careful! This test kit comes with instructions that explain how to properly perform the test. You follow the instructions to make sure the test works.
Water samples are used to determine the quality of water. A color change in the water indicates its nitrate levels.
It’s important to me to know how much nitrate is in the tap water, because I can then adjust the water for the fish. In order to be able to tell how clean your fish tank is, it is necessary to measure nitrate levels in the water. I really need to clean the tank water if has 40 ppm nitrate. If my tank water has 25 ppm nitrate, then I know that may fish tank is clean.
The amount of nitrate levels found in fresh water is a major concern to fish lovers. They are found in almost every body of water in which fish live. You should be concerned about the nitrates in the water where you keep your fish.
Fish like to live in clean, clear water, and you will have to remove any dirt, debris, or sediment that may have settled on the bottom of the tank to keep the water clean. Your fish will be happier if there is a current flowing through the water.
Your fish will experience stress when nitrate levels reach 100 ppm, and if you don’t take action to correct that, they will suffer from disease and parasites.
Nitrates in the water can be toxic to your fish, so it’s important to monitor them. High nitrate levels in the tank are also linked to water that is not adequately oxygenated.
When adding a new fish to your aquarium, look for a species that tolerates high levels of nitrate in water. These fishes are less likely to experience stress and illness.
You’ll know if your tank water is right for your fish because it should have the same numbers as the other tanks at the store, and the fish store should have those numbers, too. The chances of the fish suffering from nitrate shock or nitrate poisoning are greatly reduced if you do that.
The potential dangers of high nitrate levels
Nitrogen pollution can lead to algae problems in your aquarium, so if you’re having difficulties controlling the growth of algae in your aquarium, you may need to consider reducing the level of nitrates.
Plants need nitrogen as an essential nutrient to grow. When the nitrate levels in the water increases too fast, the algae will cover your plants, which could eventually kill them. It’s really easy to kill your plants with too much nitrogen.
When using nitrogen fertilizer, make sure the amount added to your water supply is not high, because it can cause too much nitrate in the water and algae to rise too quickly. If the nitrogen is increase slow and steady over time, the plants should grow just fine.
Nitrate Poisoning vs nitrate shock
You have two forms of nitrate toxicity: Nitrate Poisoning and Nitrate Shock.
Nitrate Poisoning
A chronic problem called nitrate poisoning can occur when nitrate levels rise slowly over weeks.
Nitrate poisoning might be related to tank conditions or stocking level, but it’s usually caused by overfeeding or poor tank maintenance. Overfeeding is the root of many problems with aquariums.
A properly maintained tank can usually take care of itself. When freshwater fish are exposed to a high nitrate levels, they can die or experience organ damage.
Juveniles and baby fish are more likely to be affected by lower nitrate levels in the water than adult fish. Sometimes just one or two fish in a tank are affected, not every fish. The effect of nitrate poisoning is generally fish death.
If you ignore nitrate poisoning, it might go on and become worse.
If you don’t test the water, the fish’s sickness can be overlooked, until it’s too late. It may take a few days or a few weeks before the fish begin to show symptoms.
Nitrate Shock
When you suddenly expose fish to a high concentration of nitrate, this is what’s called a “nitrate shock”. It is also possible that the fish are exposed to a sudden drop in nitrate levels, which may lead to more dramatic problems.
The nitrates in the water are a danger to most freshwater fish. New fish introduced to an aquarium with already very high levels of nitrates can have a “shock” reaction.
The fish are surprised to find that the water quality is so low, even though existing residents have adapted to it over time. A nitrate shock can cause fish to die in 24 hours.
You should not do major water changes to your fish tanks if they already have very high levels of nitrate.
The following symptoms can indicate a nitrate shock in your aquarium:
- slow moving or floating on the substrate
- poor appetite
- inability to swim properly
- disorientation
- gill movement
- rapid breathing rate
- curling up
Nitrates are an important part of the health of your aquarium. If you see any of these signs in your fish, test the water immediately to make sure that nitrate levels are within acceptable parameters. There are a few simple steps you can take to avoid high nitrate levels in your tank.
How to avoid high nitrate levels?
I’m going to share with you the treatment of nitrate poisoning.
Your first step should be to decrease the nitrates in the water. Although it’s very important to make sure that the water is changing gradually so that your fish won’t be shocked.
Do not feed the fish while treating the aquarium for the first 24 hours of treatment. It’s not likely that the fish will eat the food. The water problem will get worse if the food is not eaten. Uneaten food is a big reason why fish tank water is contaminated.
The tank water should be tested for nitrates, which will help you determine how many water changes may be necessary.
Safe nitrate levels in the tank
The target figure for nitrates in the water must be under 20 ppm. You will have to reduce the nitrate levels in the water by only 5% per couple of hours.
Make sure you’re adding enough water to replace around half the volume of the tank. That will drop your nitrate levels to a rate that won’t shock the fish.
After you’ve done the first round of water changes, re-test to see if the nitrate level has reduced. You’ll need to repeat this process the next day until the water level is at your desired level.
Understanding the reasons for high nitrate levels in the aquarium is important to prevent the issue from happening again.
Overfeeding
Overfeeding your fish can be bad for their health. Overfeeding leads to diseases that include bloat and constipation.
When you feed fish, they produce nitrogen as waste from their digestive processes. This creates an additional burden of toxins on your biological filtration system.
Any uneaten food can be a problem if not consumed. It can be slowly decomposed by bacteria and other microorganisms, which release toxic substances into the water
Feed your fish the right diet and provide just enough food to last for a few minutes. One of the most important things you should do for your aquarium is to feed your fish once or twice a day and include one day of fasting each week to let their systems rest.
Overstocking
Overstocking your fish tank can cause problems. Over-filling your aquarium will result in a fishy mess, and over time you’ll have too much nitrates in the water. Crowded tanks lead to stress and poor water quality.
One of the first things you should do when you are setting up a fish tank is to decide what kind of fish you want to put in it.
You should also consider the tank size and the amount of fish that you want to keep in it. It is important to be able to properly care for your fish and to monitor their growth.
Fish need about one gallon of water per pound of fish. Remember to leave room for juvenile fish to grow into larger ones. Don’t buy new stock if you don’t know the maximum size that the fish will reach when fully mature.
Also remember that some fish are territorial and need more space than others. Poor water quality is a consequence of having a crowded fish tank.
Dirty Filters
Mechanical filters need to be cleaned regularly to keep them running efficiently. They will not work if they are dirty or clogged.
Also If you don’t have a properly sized filter, this may cause poor circulation of water around the tank, and pockets of foul water.
Under such conditions, nitrites may develop. Keep the filters clean by cleaning them every month and replacing the carbon filter media regularly.
Decaying Plant
You can control your nitrate levels in your tank by keeping live plants in it. They absorb nitrates from the water, which helps keep nitrate levels down. You should maintain your plants and keep them tidy, you must also provide proper care for them. Decaying plant material produces high levels of nitrate.
Dead plants on the bottom of the tank increase the amount of nitrogen in the water. To avoid a buildup of plant debris on the bottom of the tank, remove any dead plant material as soon as you see it and cut back the amount of plants you have in the tank.
How to reduce and control the levels of nitrates in your aquarium?
Keep live plants
Keep a garden of live plants. You’ll get more nitrates out of your tank than from any other method! If you keep live plants in your aquarium, then this is a good way to maintain nitrate balance. Living plants help reduce nitrate levels in the environment by using it as fertilizer. Keeping live plants in fish tank can be a great way of controlling nitrate levels.
Keep your tank clean
When it comes to controlling nitrate levels in your aquarium, it’s best to keep it clean and well-maintained. Be sure to vacuum up any leftover fish waste from the substrate, as this will create a high-nitrate environment.
Use nitrate-removing filter media
Special nitrate-removing filters are an excellent option for tanks with a persistent nitrate problem. You can get such products online or at a good pet store.
Water changes
The fish tank should have water changed on a regular basis to remove nitrates from the water and prevent algae buildup. The problem with tap water is that it might have high nitrate levels. Water changes helps to reduce the amount of nitrate in tank.
You can use DI water, or reverse osmosis water, for water changes. But in fact neither option has any mineral content, so the water pH and hardness can change. Adding an additional pH buffer or a trace mineral supplement might be necessary.
You can also mix the right proportions of distilled or reverse osmosis (RO) water with tap water to create a blend of water that you want.
Use a denitrator filter
If you notice high nitrate levels, using denitrators can be beneficial; however, there are also other methods of reducing nitrates that are cheaper than this type of treatment. These include media such as bio-granular activated carbon, but this has to be replaced periodically.
Microbes
In the aquarium, there are various microbes that can be used to control nitrate levels. We know that aerobic microbes are the ones that help us in controlling nitrates because they consume nitrogen. Aerobic microbes are known for doing their job quickly.
However, we need to be aware that there are some problems that come with using aerobic microbes. For example, they can easily overgrow and consume too much oxygen, which will deplete oxygen in the water.
Oxygen depletion will make it difficult for fish to breathe. A better way to control nitrates is to use anaerobic microbes. Anaerobic microbes are slow in the beginning and then they speed up.
In conclusion
When it comes to aquarium maintenance, the perfect storm is to create a diverse and varied microbial community. A deep sand substrate, regular feedings, and bacterial food supplements and inoculants are all important in maintaining a healthy aquarium.
If you would like to keep your aquarium clean and well-maintained, you should make sure that your water changes take place regularly.
If you do this, you will be able to eliminate unnecessary contaminants (including nitrates) from your aquarium and maintain a healthy environment for your fish. Another thing that you can do to reduce nitrates in your tank is to regularly clean the gravel and filter media.
As I explained, excess nitrates are the number one cause of fish disease in fish tanks. I hope this information helps you.
