How to increase oxygen in fish tank?

Aeration of water in the aquarium

Oxygen is a necessary element in your aquarium. Fish need it to breathe, plants need it at night, and bacteria use it to break down waste.

In general, everything that dies or decomposes in fish tank needs and depletes oxygen. Here I’m going to teach you some ways to increase oxygen in your tank instantly.

At the beginning, it is also worth explaining what is the difference between oxygenation and aeration. Both of these processes lead to one result: increasing the oxygen level in the tank.

Oxygenation is nothing more than the state of oxygen saturation. Gas exchange takes place on the surface of the water. Water absorbs oxygen and releases carbon dioxide.

This gas exchange causes the oxygen to dissolve in the water. How much oxygen dissolves in the water is called oxygenation.

Aeration is related to the movement of water and it is a process that you initiate yourself. This applies to the flow and current of the water. The aeration is designed to distribute oxygen-rich water throughout the entire tank.

If it weren’t oxygenation process, it would not be possible to distribute it in water. Aeration, i.e. the movement of water, is necessary to ensure proper oxygenation of the tank.

Stagnant waters always have a lower dissolved oxygen level. It’s when there isn’t enough water movement.

What are the factors that affect the amount of oxygen that can be dissolved?

Oxygen is produced in an aquarium in two ways:

1. Through the process of gas diffusion between water-air media
2. As a result of photosynthesis that takes place in the presence of light. In the absence of light, plants take oxygen from the water.

The amount of oxygen that can be dissolved depends on many factors:

• The ratio of the surface of the reservoir to the entire mass of water contained in it – the larger the surface of the water table, the easier the dissolution of oxygen in the water
• The degree of disturbance of the water surface – dynamic water flow (waves, cascades) increases the efficiency of water oxygenation compared to static tanks
• Tank depth – the deeper the tank, the smaller the amount of dissolved oxygen at the bottom
• The time it takes to reach stability between the oxygen concentrations in the water and the atmosphere in the air
• Water temperature – the higher the temperature, the lower the solubility of oxygen in water; at higher temperatures, the rate of biochemical processes consuming oxygen increases
• Surrounding pressure – the lower the pressure, the lower the solubility of oxygen in fish tank
• The intensity of photosynthesis – this process is strictly dependent on the intensity of light, the level of CO2 in the water and the water temperature (under favorable conditions, the oxygen concentration may increase by as much as 1 mg/l)
• The salinity of the reservoir – as the salinity of the reservoir increases, the solubility of oxygen decreases
• Substances lying on the water surface – for example oils or a protein membrane effectively inhibit the process of gas exchange between two water-air centers

When are we talking about full saturation?

When the dissolved oxygen in tank is in balance with the oxygen in the atmosphere. However, it should be remembered that the average saturation in an aquarium is 70%.

Dissolved oxygen levels may fluctuate throughout the day. When the lights are turned on, the water in the aquarium gets oxygenated. The lowest concentration is reached in the morning.

We talk about oxygen deficiency when there is a difference between the saturated oxygen concentration under given conditions and its actual level in water.

Water saturation with oxygen and other gases occurs when the concentration of dissolved oxygen in fish tank is greater than in the atmosphere (under the same conditions). The effect of water supersaturation is gas disease in fish.

30% supersaturation of the water causes the fish to die.

What is the effect of hypoxia in fish tank?

– diseases of fish and other organisms

– algae bloom

– the death of plants due to the growth of macro and microelements

– it intensifies the processes of denitrification and ammonification (due to the formation of anaerobic conditions in the organic matter lying on the bottom)

As a rule, there is enough oxygen in the aquarium. Too low oxygen level can have many causes.

What is the cause of low oxygen level in water?

– Low lighting – plants produce oxygen during the lighting period and consume it at night

– Overstocking – more fish means more waste which in turn requires more bacteria to oxygenate them

– Low water movement

– Waste accumulation in the filter or in the gravel

– Chemicals and medications

We use additional aeration of water in our tanks when we observe that our fish gasping at the surface and we have eliminated other causes that contribute to this state. It is also worth considering additional water aeration in the case of a large plant population compared to a small number of plants.

Aeration with additional aquarium devices is an artificially induced process aimed at introducing oxygen into the water and equalizing its concentration at each point.

What factors affect the efficiency of water oxygenation?

– water temperature – with increasing temperature, the solubility of oxygen in water decreases

– the size of the air bubbles – the larger the bubbles, the lower the amount of oxygen supplied and the worse its utilization

– water movement – forces the bubble to travel longer and equalizes the oxygen concentration at each point

– the length of the bubble – the longer it is, the more time it takes for the oxygen to penetrate the water

– the permeability of the surface layer – if it is blocked, the penetration of oxygen is significantly limited (e.g. by the presence of a protein membrane)

Additional aeration in the aquarium can be done using the following equipment:

– a large number of plants – this is a natural way

– filters with the function of additional aeration or by appropriate setting of its outlet

– spray bar – to agitate the water surface

– air pump (diaphragm pump – pump forcing air through the diaphragm piston pump – air is pumped through a moving piston in the cylinder)

– aeration turbine – air is pumped by means of a rotor

– wavemaker

– HOB filter

– fountain

When choosing equipment, we should pay attention to several important elements:

– performance

– power

– maximum lifting height

– the maximum capacity of the tank that it can handle

– the ability to regulate the capacity

– number of air outlets

– number of membranes

You should remember about it in order to maintain adequate amounts of oxygen in the aquarium. You also need to know what to do in the event of an oxygen crisis. How to know if your tank has a low oxygen level? What symptoms in fish should worry you?

– lack of appetite or lethargy of the fish 

– the fish catches air on the surface

– algae growth

– bubbles in the aquarium when the water returns

– condensation on the walls of the aquarium

– the fish gather near the filter drain

With low oxygen level, we are unlikely to observe the above symptoms. However, if we notice any disturbing symptoms, we must take care of the right amount of oxygen in the fish tank as soon as possible.

It is worth getting a good quality liquid test kit.

What are the methods for measuring the oxygen levels in an aquarium for hobbyists?

When it comes to measuring dissolved oxygen levels in an aquarium, hobbyists typically have two options to choose from. One of them, being the more budget-friendly option, we will discuss first.

Dissolved Oxygen Test Kit

If you’re familiar with testing the pH of your aquarium, you’ll know that colorimetric tests are commonly used.

Dissolved oxygen test kit work in a similar way, and they can be used to check the oxygen levels in your aquarium.

All you have to do is add the drops to a sample of your aquarium water and compare the color to the chart to determine the amount of dissolved oxygen in your tank.

While more expensive test kits tend to be more precise, hobbyists usually just need a rough idea of their dissolved oxygen levels.

Many test kits can perform multiple tests, like the Salifert test, which can be used for over 40 tests.

Dissolved Oxygen Meter

For those who have the budget, a dissolved oxygen meter provides quick and precise measurement of the oxygen levels in your aquarium.

Simply insert the probe into the tank and the oxygen level will be displayed on the LCD screen.

While a dissolved oxygen meter may be more accurate than a test kit, it does require ongoing maintenance to maintain its accuracy.

This includes replacing membranes and batteries, and regular calibration.

However, if you are looking for the most precise measurement of dissolved oxygen, a dissolved oxygen meter is the way to go.

Ways to increase oxygen in your tank in case of emergency

There are several ways to increase the amount of oxygen in your fish tank. 

Pouring water from a certain height

Pouring water from a height into the fish tank will cause bubbles and thus increase the oxygen level. It is best to pour water from a certain height in the center of the tank so that it is evenly distributed.

For this procedure, it is enough to use an ordinary bottle or water from a hose. 

Be careful that too much pressure does not blow up your fish. The quality of the water that you pour into the aquarium is also important.

It’s a good idea to use dechlorinated water and make sure the pH is in the correct level. You can use this solution in case of emergency. 

Water changes

A large water change with oxygen-rich water can increase oxygen in the fish tank. Excessive waste reduces the oxygen carrying capacity of the fish tank.

To effectively increase the oxygen concentration in the fish tank, you need to change the water by at least 30% or even more.

Although I do not recommend major changes in this case, they are only an emergency intervention. Let’s use dechlorinated tap water in this case.

When pouring water, remember not to disturb the gravel ground. This can make it cloudy, reducing the oxygen level. Also, adding plenty of fish and plants will effectively reduce the oxygen level.

Ice cubes

This is another way to increase oxygen in your fish tank.

Low water temperatures usually have a higher oxygen content. If we desperately need a boost of oxygen in the tank, it may be useful to lower the temperature.

In this case, we can put the ice cubes in a bag (an airtight bag can help us) and put it in the fish tank. This treatment can raise oxygen levels by up to 4 ppm . We should not add ice cubes directly to the fish tank as this can cause harmful fluctuations in water temperature.

In addition, along with the ice cubes, you expose your aquarium to pollution and bacteria. You must also remember to keep the temperature in the range preferred by the fish.

If your fish like a temperature range of 70 to 80 degrees F, shoot the temperature on that spectrum. Although lowering the temperature can raise the oxygen level, it can also harm your fish if we do it very abruptly.

Use a battery-operated air pump

It is not necessary to use an air pump, but many aquarium handbooks may recommend it. In the event of a power outage, the use of a battery-powered air pump can be a bull’s eye.

In these situations, electrically powered air pumps will simply stop working. Remember that the pump will work as long as the batteries. It is worth getting additional batteries or planning an appropriate charging plan.

In large tanks, an air pump can produce less water flow than an electrically powered air pump. In this case, we can use more than one pump to  increase the oxygen level in the aquarium 

Ways to increase oxygen in the fish tank (Permanent solutions)

The above examples are ways to temporarily increase the oxygen in your aquarium. They are great in case of emergency.

There are many long-term solutions to help you maintain a healthy oxygen level in your fish tank. The other ways include using a HOB filter, spray bar, fountain, air pump and wavemakers. 

HOB filter

It is great to increase the oxygen level in your fish tank.

HOB filter is very easy to use and does not take up much space. This type of filter works perfectly as an oxygenator.

Properly filtered water will fall into tour aquarium from above, which will oxygenate the water.

The HOB filter will not only allow you to maintain an appropriate level of oxygen, but also help maintain high water quality. The HOB filter is effective for additional oxygenation, but it is one of the less efficient filters.

Many aquarists prefer rather strong types of filters, such as the canister filter. HOB filter is usually below the water surface, which makes it difficult to aerate the fish tank.

Spray bar

Using a spray is good way to increase the oxygen levels.

It is usually used in conjunction with canister filters. The spray bar allows you to distribute the already filtered water over the entire surface of the tank.

Such action will effectively aerate the water, which will increase the oxygen level in the aquarium.

The sprayer should be placed at such an angle that it points towards one side of the tank. The gentle waterfall effect will disperse oxygen-rich water throughout your aquarium.

This is a very effective way to increase the amount of oxygen, but for larger and deeper tanks it may be necessary to use several sprinklers to achieve a specific oxygenation level.

Use a fountain

Another way to increase the oxygen levels in your tank is by using a fountain heads.

The fountain heads creates an amazing visual effect in the tank. Like matters, fountain bars move the surface of the water, which increases the amount of dissolved oxygen in it.

There are many fountain heads to choose from, so you have to choose the one that will fit the size of your tank. It is worth choosing a fountain with adjustable water flow, which will allow you to minimize the negative effects of strong currents.

The fountain heads are easy to install, they are only suitable for large reservoirs or ponds.

Air pump

Using a battery-powered air pump is a very easy way to increase the oxygen level in the aquarium.

The air taken in by the pump is released into the reservoir by the air stone. Air bubbles rising to the surface of the tank develop the water with oxygen.

The battery-powered air pump should be installed in such a way that the bubbles have a long time to reach the water surface. This will increase the oxygen exchange. One disadvantage is that the air pumps are relatively noisy.

Wavemakers

By using a wave generator, you can effectively increase the oxygen level oxygen level in the aquarium.

The inverter circulates the water. Waves that spread across the surface of the water bring air into contact with the water, which allows the gases to exchange.

We can buy electronic and mechanical inverters in stores. Both will help you increase the oxygen level in the aquarium, but an electrically powered inverter will be a better solution.

They are very energy efficient and quieter. The undulating device should be positioned properly. The inverters have adjustable water flow speed, so we can adapt to different fish requirements.

What affects the low amount of oxygen in the fish tank?

Overstocking

Too many fish is a common cause of low oxygen level in the aquarium. If you put a lot of fish in a small aquarium, the tank will eventually run out of oxygen.

The number of fish should be selected depending on the size of the tank. It is worth keeping fish that swim in different levels of tanks. Let’s choose those that float on the bottom, in the middle and near the surface.

The fish will help disperse the oxygen-rich water throughout the fish tank. Fish swimming in shoals will be ideal.

Low water circulation

Poor or no water movement also causes low oxygen levels. It is also related to the build-up in the filter system. If you filter is clogged, it will significantly reduce its flow, which will limit the movement of water.

Low lighting

This applies in particular to tanks with a large number of plants.

In general, plants cause an increase in oxygen levels because they take carbon dioxide from the water and oxidize oxygen. This form of gas exchange provides not only a natural living environment, but also maintains an appropriate level of oxygen.

In the case of low light, instead of taking up carbon dioxide and releasing oxygen, plants will take up and release CO2, which will lower the oxygen level in the aquarium.

High temperature

Too high temperature affects the oxygen level in your tank.

Warm water promotes the growth of harmful bacteria and also makes it difficult for fish to breathe. If we have a problem with the aquarium heating up, you can use a cooling unit in the aquarium system.

The chillers allow the water temperature to be lowered, which in turn reduces the need for oxygen. The principle is that the colder the water, the more oxygen it contains.

You should, of course, take into account the requirements of your fish and not go beyond certain limits.

Before buying, make sure what temperature range is the best for your fish. You can find more about aquarium cooling here.

Chemicals and medications

When using chemicals or certain drugs, the oxygen level in the aquarium may be low.

In general, it is a good idea to limit the administration of any chemicals. I promoter chemicals and drugs as a last resort. If you treat your fish, make sure that there is adequate water flow and circulation.

Remember that unwanted substances may also be in your tap water. Before adding it to your aquarium, I recommend that you test the water and use a conditioner (such as PRIME) if necessary.

It’s important to always advocate for chemicals and medications treatments as a last resort.

As we have seen, oxygen deficiency can have dire consequences. By following these tips, you can make sure your fish never run out of oxygen.

The amount of oxygen in your aquarium may also be too high. It may be related to:

– too strong a filter – too strong a filter or too high water flow not adapted to the size of the aquarium can have opposite effects

– too many aerators – if you have many aeration devices in the aquarium (spray bar, air pump, fountain, etc.), it is better to limit yourself to one solution

Your aquarium should have a filter adapted to the size of the tank. In the case of aeration devices, let’s determine the appropriate configuration. You may find that you only need one device to meet your oxygen demand and maintain its optimal oxygen level.

In conclusion

There are many different ways to quickly increase oxygen in fish tanks. Some people pour water from a height, others perform large water changes. If you add fresh oxygen-rich water to your tank, it will help the fish to thrive.

Some more permanent methods, such as using a spray bar or HBO filter, should help to prevent oxygen levels from dropping.