Effects of Ammonia in a Planted Aquarium

Understanding your aquarium plants and their requirements is essential when you want to have a well-maintained planted tank. Likewise, knowing how different gases are formed in the aquarium and how they affect the plants and other living organisms is equally important.

Out of all the gases in a tank, ammonia (NH3) is one of the most misunderstood and feared ones. While it is not a toxic gas in general, when in excess, it can cause severe problems for both fish and invertebrates. But what about live plants? Does it pose harm to the aquarium plants in a planted tank as well?

This is one of the most commonly asked questions by novice and learner aquarists, and the article will help you understand the same.

The relationship between ammonia and aquarium plants is shady. While in some cases it may harm the plants, in others it may help them grow better. Therefore, knowing how ammonia can affect a planted tank, at which level it can pose harm to the plants, and how to deal with or manage it is important. So, keep reading to know all about ammonia through an aquarist’s point of view.

What is Ammonia?

Ammonia is a highly soluble, colorless gas that is produced as a waste product in the aquarium through leftover food particles, fish excreta, dead and decaying plants and animals, and decomposition of organic matter.

It has a sharp and pungent odor. In an aquarium, it can occur in two forms– NH3 and NH4. While NH3 or ammonia gas is highly toxic and unionized, NH4 or ammonium is less toxic and ionized. Now, which form is available in the tank decides how it will affect the living organisms inside it.

Usually, it depends upon 2 factors– the tank’s pH and temperature. If the pH is acidic or less than 7, ammonia occurs in ammonium form. On the contrary, at high pH and high temperature, it starts shifting to the NH3 form.

Importance of ammonia

Ammonia is essential for accomplishing the Nitrogen Cycle, which is an important part of a well-established planted tank. It is the Nitrogen cycle wherein all the dead and decaying matter of the tank is broken down into nitrite and nitrate by beneficial bacteria. In this way, nitrogen flows in the water and is subsequently taken up by the aquatic plants for living.

However, if there is a lack of beneficial bacteria in the tank or biological filtration is insufficient, ammonia can spike to levels that become harmful to the life in the aquarium.

Effects of Ammonia in a Planted Aquarium

As already mentioned, ammonia can affect plants differently. While for some plants it can be dangerous, for the rest it could be highly beneficial within the right range.

A- Beneficial effects of ammonia on aquarium plants

Plants require nitrogen as one of the macronutrients for thriving, and for aquarium plants, ammonia becomes that source. In fact, plants prefer ammonia as their source of nitrogen in water. It is because assimilating nitrogen in that form is easier for the plants, and when present in proper concentration, nitrogen stimulates growth.

If your planted aquarium has plants like Vallisneria, Amazon Sword, Hornwort, water sprite, or species of Hygrophila, they readily absorb a small amount of ammonia. These are usually fast-growing plants and act as natural biofilters. In this way, they maintain the level of ammonia under control, thereby preventing it from harming the fish in any way.

B- Harmful effects of ammonia

Ammonia becomes harmful to the aquarium life only when its concentration goes above and beyond the limit. Plants utilize some concentration of it effectively; however, as the concentration rises, ammonia becomes harmful.

Below are some of the negative effects of ammonia that you may encounter in your plants-

1. Damaged leaf because ammonia damages the plant’s cells and leaf tissues
2. Melting of leaves, which can be commonly seen in crypts
3. Browning of leaves or having black spots
4. Yellowing of leaves, also called chlorosis
5. Melting of aquatic plants that are delicate and have thin leaves
6. Disruption of the uptake of other nutrients
7. Algae bloom because high ammonia leads to excessive growth of green water and hair algae
8. Poor root growth

Therefore, it is important to take steps to keep ammonia concentration within the tolerable range of plants. Under high concentration, that is, more than 1.0 ppm, the plants are likely to suffer. Likewise, if the tank has poor lighting and a low concentration of carbon dioxide, the level of ammonia will spike. When all these factors are combined with nutrient imbalances, there is a high chance that you will experience stress in aquarium plants.

Sources of ammonia in a planted tank

Ammonia comes from varying sources, and for managing its level, knowing from where it comes is important. Below are the common sources of ammonia-

• Fish waste (excreta)
• Plant waste (dead and decomposing plants)
• Inadequate or incomplete biological filter
• Soil substrates that are new may leach ammonia.
• Tap water

Nitrogen Cycle in Planted Tanks

Beneficial bacteria present in an aquarium break down ammonia into its less toxic forms. However, if the tank is heavily planted and the dead and decomposing material, also called bioload, is less, plants can outcompete bacteria for ammonia.

Many aquarists perform a fishless cycle. It is running the tank when fish are not present. In this way, everything runs naturally and all byproducts flow before fish are introduced. Fishless cycle with plants is also practised by many, which is simply running the fishless cycle without ammonia when there are plants. It is also suggested to add plants to balance ammonia so that the need of filters and chemicals reduces.

Testing and Monitoring Ammonia

Now that you know how important it is to keep the concentration of ammonia under control, it’s time to test and monitor it. You can get an aquarium ammonia test kit to keep an eye on the ammonia levels. This should not be skipped, especially if you have a new setup, added fresh livestock recently, or increase the feeding of your fish. Also, it becomes an essential monitoring step when you are using a nutrient-rich substrate.

Since ammonia is related to nitrogen, any issue with it means it’s an issue with the nitrogen, and this can affect the life of your aquatic plants.

Usually, the testing kits have strips that you need to dip in water to know the levels of chemicals in your tank. These strips give a fair idea about the different chemicals, including NH3, NH4, and more, present in the water.

Below are the safe levels of ammonia in an aquarium with live plants-

• 0 ppm NH3 is the most suitable
• Total ammonia levels less than 0.25 ppm are considered safe in a planted tank
• More than 0.5 ppm is potentially harmful not only for plants, but also for fish and invertebrates too

How can you manage ammonia in a planted tank?

As we know what spikes the concentration of ammonia, managing those factors can help curb the problem to a great extent. Below are some simple measures that you can take to manage ammonia in a planted tank-

1. Cycle the tank

Before you think of introducing any fish or plants to the aquarium, make sure the tank’s nitrogen cycle has completed. There should be something for bacteria to feed on during cycling, such as ammonia or fish food. In the end, ensure that the concentration of ammonia and nitrite is 0 ppm.

2. Maintain the right plant-to-fish ratio

Overcrowding a tank with a lot of plants or overstocking the fish will automatically increase the level of ammonia. Therefore, research before adding both plants and fish, and do not neglect the tank size while making the choice.

3. Do not overfeed

Leftover food particles that settle at the bottom not only make the water look dirty but leads to increasing ammonia as well. So, feed mindfully and only what your fish will consume within 2 minutes. Overdoing it will again add to increasing ammonia.

4. Change water regularly

Include a weekly water change in your routine now. You only need to change around 20 to 50% of the water. It will dilute built-up ammonia.

5. Maintain healthy plants

Provide adequate lighting of around 6 to 8 hours, along with carbon dioxide and fertilization, so that your plants stay healthy. Do not forget to add macronutrients and micronutrients in your tank for the right growth.

Final Words

In a planted aquarium, ammonia can work both as an angel and a devil. If you worry and think that ammonia will kill the plants, the article must have helped you understand all the whys and hows about it.

Ammonia can be harmful and beneficial– it’s all about its concentration. Make a habit to regularly monitor the water using testing strips if you think the plants are in stress due to ammonia. Understand the role of the nitrogen cycle, add aquatic plants that absorb ammonia and maintain water quality for a healthy, lively, and beautiful lush green aquarium.