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 get to the bottom of the confusion in aquarium hobby: nitrate.


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


. Although nitrate is less toxic than ammonia in small amounts, it can still cause serious health problems for animals. 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. Simply submerge a test strip into the aquarium water and swirl it underwater for three 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.

Use multi-test strips for measuring nitrate and other water parameters.

What are the Safe Levels of Nitrate for Aquariums?

Ammonia and Nitrite are toxic to some animals, but nitrate is far less toxic. However, little research has been done to determine how toxic nitrate is to all of the different animals we can keep in our aquariums. A research paper entitled Nitrate toxicity to aquatic animals states that nitrate levels reached 800ppm in order to make them lethal for guppy fry. We personally recommend keeping less than 80-100 ppm nitrate in your fish tanks.

Many people see this upper limit for nitrate and assume that, for the health of their aquarium animals, it would be best to lower nitrate as much as possible. Live aquarium plants need nitrate to thrive. Fish, shrimp, and snails do not suffer from a lack of it. The nitrate levels drop to 0-20ppm and leaves turn yellow or translucent, especially at the tips. They then have to use nutrients from their old leaves at bottom to make new leaves. In our tanks, we aim for 50 ppm nitrate.

Signs of nitrogen deficiency

How to Lower Nitrate in High Bioload Tanks

Fish tanks that are overstocked with fish or have few aquarium plants can lead to a naturally high level of nitrates. A partial water change is the fastest and most effective way to reduce nitrate levels in an aquarium. Use an aquarium siphon to remove 30-50% of the old, nitrate-laden liquid and then refill the tank with clean, fresh 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. This flow chart will show you how to make water changes.

Most people don’t like frequent water changes. Let’s examine some methods to maintain lower nitrate levels. Aquariums with high bioload are more likely to have high levels of nitrate. This means that there is a lot of fish waste, leaves and other rotting organics 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 don’t want to reduce your fish population, consider upgrading the aquarium or adding large numbers 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.

Are Fish Poop and Aquarium Plants a Good Enough Fertilizer?

Besides light and water, plants require an exact mix of nutrients to give them the fundamental building blocks needed to survive and 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. When beginners try to keep plants without any fertilizer, the plants often develop serious nutrient deficiencies within a few months. To address this common problem, we developed Easy Green as an easy, all-in-one fertilizer to help keep plants healthy and well-fed.

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. Easy Green can increase the nitrate level when tested with a water test strip. In fact, the goal is to dose enough Easy Green until the nitrate level reaches 50 ppm.

How to keep the right amount of Nitrate in Aquatic Plants

How can we achieve the perfect concentration of nitrate in our aquariums without having too little or too much? You can see that your aquarium is consistently producing nitrate.

too much nitrate

You may feel tempted to stop using Easy Green as it will increase nitrate levels. However, withholding fertilizer may end up depriving the plants of other essential nutrients besides nitrate. These are the steps to prevent this:

1. If nitrate is 50 ppm or above, do a 50% water change (or multiple 50% water changes every four days) until nitrate reaches 25 ppm at most. 2. One pump of Easy Green for every 10 gallons water. Give the water a rest for a few hours before testing it again. 3. Your goal is to achieve 50 ppm of nitrate. If the nitrate level is still low, you can repeat Step 2. You will continue to apply fertilizer until it reaches 50 ppm. 4. Give the water a rest for 3-4 days, then test it again. You will need to change 50% of the water if the nitrate level is higher than 75-100ppm. Consider removing some fish or adding more plants (especially fast-growing ones) to decrease the rate at which nitrate is accumulating.

Quick Dosing with Easy Green all in one fertilizer

However, if your plant tank has to little nitrate you need to fertilize regularly to prevent starvation. As a starting point, we recommend dosing 1 pump of Easy Green per 10 gallons of water with the following frequency:

– Dose once a week for low light aquariums. For medium-light aquariums, do twice per week.

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

You should keep track of the fertilizer used and the dates that you fertilized the tank. Soon you will be able figure out your personal dosing schedule. If you have trouble doseing enough fertilizer, decrease the lighting or CO2 injection. Then repeat the previous steps. Keep in mind that aquariums can become larger or smaller as fish and plants are added to them. This will affect the amount of fertilizer that is required.

The bottom line is don’t be alarmed if your nitrate readings are higher than 0. Nitrate can be good for plants. That is why we created Easy Green as a beginner-friendly fertilizer so you don’t have to measure out a lot of supplements. Just add 1 pump per 10 gallons and watch your plants grow.