Is Nitrate Good or Bad for Your Aquarium?

Is Nitrate Good or Bad for Your Aquarium?

If you search online for information about nitrate in fish tanks, many articles immediately pop up to warn you about the dangers of high nitrate and the best methods for lowering it. How much nitrate can be considered to be dangerous? What if nitrate is so dangerous, then why are many aquarium fertilizers increasing nitrate levels? Let’s discuss nitrate, which is the most confusing aspect of aquarium hobby.


What is Nitrate?

Fish and other animals waste toxic nitrogen compounds such as ammonia when they eat and poo in an aquarium. Beneficial bacteria in the fish tank naturally grows and consumes the ammonia, purifying the water in the process and making it safe for fish to live in. However, one of the end products generated by the beneficial bacteria is


. While nitrate is much less toxic than ammonia it can also cause harm to animals in large quantities. For more information, read The Easy Guide to the Nitrogen Cycle for Aquariums.

How to Measure Nitrate

Since nitrate can’t be seen with the naked eye, it is neither colorless nor odorless. Fishkeepers typically measure it using water test strips or chemically reacting kits. Aquarium Co-Op Multi-Test Strips, for example, measure nitrate along with five other parameters in less than a minute. Just dip the test strip in the aquarium water until all test pads are covered. Then, gently swirl the strip underwater for 3 seconds. Then remove the test strip out of the fish tank without shaking off the excess water and keep it horizonal for 60 seconds. As soon as the time is up, immediately compare the results with the included color chart to read the nitrate amount.

Multi-test strips are used to measure nitrate and other parameters.

What are the Safe Levels of Nitrate for Aquariums?

While some nitrogen waste compounds like ammonia and nitrite are toxic to animals at even trace amounts, nitrate is considerably less toxic. It is not known how toxic nitrate really is for all species of animals that can be kept in aquariums. As a frame of reference, a research paper titled Nitrate toxicity to aquatic animals reports that nitrate concentrations were raised up to approximately 800 ppm before they became lethal to guppy fry. We personally recommend keeping less than 80-100 ppm nitrate in your fish tanks.

Many people assume that the upper limit of nitrate is too high and therefore lower it as much as possible to ensure their aquarium animals’ health. While fish, snails, and shrimp are not affected by the lack of nitrate, live aquarium plants absolutely need it to grow well. Plant leaves can become translucent or yellowish if the nitrate level drops below 0-20ppm. This is because the plant has to consume nutrients from the bottom to grow new leaves. Therefore, we aim to keep approximately 50 ppm nitrate in planted tanks.

Signs of nitrogen deficiency

How to lower Nitrate in High Bioload Tanks

A fish tank with a high level of animals or a low number of plants can cause nitrate levels to rise to as high as 80-100ppm. A partial water change is the fastest and most effective way to reduce nitrate levels in an aquarium. You can remove 30- to 50% of the old, nitrate laden water with an aquarium siphon. Then, you can refill the tank again with fresh, clean water. We don’t want to shock the fish with huge water changes. If your nitrate level exceeds 100 ppm, multiple water changes may be necessary over several days. Our flow chart for water modifications provides a step-by guide.

Most people don’t like frequent water changes. Let’s examine some methods to maintain lower nitrate levels. Aquariums that have high bioload often have high levels of nitrate. This is because there are lots of fish poop, leftover food and other rotting materials in the water. Hence, the easiest methods to reduce nitrate in the long term include decreasing the number of fish and/or amount of food that goes into the tank. If you’re not keen on reducing your fish population, then try upgrading them to a bigger aquarium or adding large quantities of live plants. We love aquatic plants as they naturally consume nitrogen, which allows them grow more leaves and roots. Pogostemon and water sprite are faster than slower-growing plants like anubias or java fern at eliminating nitrate.

Is Fish Poop a Good Enough Fertilizer for Aquarium Plants?

Plants need more than light and water. They also require the right nutrients to provide them with the essential building blocks they need to thrive.


are nutrients that plants consume in significant quantities (such as nitrogen, phosphorous, and potassium), whereas


There are trace amounts of nutrients that plants require, such as iron, manganese, and boron. Traditionally, it was thought that fish poop and uneaten fish food were sufficient sources of nutrients for plant growth, but in reality, they do not contain all these necessary nutrients in the right ratios or amounts. Plants that are kept by beginners without fertilizer often suffer from serious nutritional deficiencies in a matter of months. Easy Green, a simple, all-in one fertilizer, was developed to solve this problem.

Easy Green’s purpose is to increase nitrate (or nitrous oxide) so that plants can eat enough. The percentages of potassium, phosphate and nitrate are actually higher than the rest, because these macronutrients are more important for plants. As a result, adding Easy Green will increase nitrate when measured by a water test strip or kit. In fact, the goal is to dose enough Easy Green until the nitrate level reaches 50 ppm.

How to Maintain the Correct Nitrate Level for Aquatic Plants

How do you achieve the right concentration of Nitrate? You can see that your aquarium is consistently producing nitrate.

Too much nitrate

Easy Green may cause a rise in nitrate so you might be tempted not to use it anymore. However, withholding fertilizer may end up depriving the plants of other essential nutrients besides nitrate. To prevent this from happening, use the following instructions:

1. Do a 50% water change if nitrate levels are 50 ppm or higher. Repeat this four times per day until the nitrate drops to 25 ppm. 2. Dose 1 pump of Easy Green per 10 gallons of water. Allow the water to cool for at least 24 hours, then test it again. 3. The goal is to reach 50 ppm nitrate. If the nitrate remains too low, continue with Step 2 until it reaches 50ppm. 4. Give the water a rest for 3-4 days, then test it again. If nitrate is already at 75-100 ppm, you will have to do another 50% water change. You can reduce the rate at which nitrate accumulates by removing fish or adding plants, especially fast-growing ones.

Quick dosing with Easy Green all-in-one fertilizer

To avoid starving your plants, however, it is a good idea to regularly fertilize your tank with too much nitrate. We recommend that you use 1 pump of Easy Green for every 10 gallons water.

For low light aquariums, you should do once per week. Medium light aquariums require twice each week.

You may need to adjust the amount of nitrate in the water if your plant leaves continue to develop holes or melt away.

Keep track of when you fertilized your tank and how much Easy Green you used. You will soon be able to calculate your custom dosing schedule. If you are unable to dose enough fertilizer to reach the nitrate goal, try decreasing the amount of lighting and/or CO2 injection and repeat the previous steps. You should also be aware of the fact that fish and plants grow larger and require more fertilizer. If this happens, adjust your schedule accordingly.

Don’t worry if you see nitrate levels higher than 0ppm. Nitrate is good for plants and even essential. Easy Green is a beginner-friendly fertilizer that you can use without measuring out many supplements. Just add 1 pump per 10 gallons and watch your plants grow.