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. But how much nitrate is considered dangerous? Why is it that aquarium fertilizers can increase nitrate levels even though they are safe for snails, fish, and shrimp? Let’s discuss nitrate, which is the most confusing aspect of aquarium hobby.


What is Nitrate?

When fish and other animals eat food and poop in the aquarium, their waste produces toxic nitrogen compounds like ammonia. The fish tank has beneficial bacteria which naturally grows and eats the ammonia. It makes the water safe for fish to swim in and purifies it. However, one of the end products generated by the beneficial bacteria is


. Nitrate is significantly less toxic than ammonia, but in large amounts, it can also start to negatively impact animals. For more information, read The Easy Guide to the Nitrogen Cycle for Aquariums.

How to Measure Nitrate

Since nitrate is not visible to the naked eye because it is both colorless (and odorless), fishkeepers often measure it with water test strips, or other kits that chemically react with the nitrate in their water. Aquarium Co-Op Multi-Test Strips measure nitrate quickly and five other parameters in under a minute. Simply submerge a test strip into the aquarium water and swirl it underwater for three seconds. Next, remove the test strips from the aquarium and let it sit horizontally for 60 second. Instantly compare the results with your color chart to determine the nitrate level.

Multi-test strips may be used for measuring nitrate, as well as other water parameters.

What are safe levels of nitrate in aquariums?

While some nitrogen waste compounds like ammonia and nitrite are toxic to animals at even trace amounts, nitrate is considerably less toxic. There has not been enough research to determine the toxic effects of nitrate on all the species we can keep 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 recommend that fish tanks contain less than 80-100ppm nitrate.

Many people view this as the maximum level of nitrate, and believe that it is best to reduce it as much possible for their aquarium animals’ health. Although fish, shrimp, and snails are not affected by a lack of nitrate in their aquariums, they do need it for good growth. The nitrate levels drop to 0-20ppm and leaves turn yellow or translucent, especially at the tips. They then have to consume nutrients at the bottom to make new leaves. We aim to maintain a minimum of 50 ppm of nitrate in our 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 a rise in nitrate levels to 80-100ppm. It is possible to quickly reduce the nitrate level by changing only a portion of the aquarium’s water. Take out 30-50% of the old, nitrate-laden water using an aquarium siphon and refill the tank with fresh, clean water. Generally speaking, we want to avoid shocking the fish by doing huge water changes, so if your nitrate level is far greater than 100 ppm, you may need to do multiple water changes over the course of several days to safely lower the nitrate. This flow chart will show you how to make water changes.

Since most people don’t enjoy doing frequent water changes, let’s look at some approaches for keeping nitrate levels lower in the first place. 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 don’t want to reduce your fish population, consider upgrading the aquarium or adding large numbers of live plants. We love aquatic plants because they naturally consume nitrate as food, allowing them to 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?

Plants require a precise mix of nutrients in order to thrive and survive, and light and water are not enough.


Plants need nutrients in significant amounts (such as nitrogen and phosphorous).


are nutrients that plants need in trace amounts (such as iron, boron, and manganese). It was believed that fish poop or uneaten fish foods were enough nutrients to support plant growth. However, in reality they don’t contain all the necessary nutrients in the correct amounts. Many plants suffer severe nutrient deficiencies when they are left to their own devices by novices who attempt to maintain them without fertilizer. 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 was created to increase the nitrate or nitrogen in plants. 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 Maintain the Correct Nitrate Level for Aquatic Plants

How can we get the right concentration of Nitrate without having too many or too few? If your planted aquarium consistently has

too much nitrate

Easy Green can be tempting to stop because it increases nitrate levels. Withholding fertilizer could result in plants being deficient in other nutrients, as well as nitrate. These are the steps to prevent this:

1. You can do a 50% water-change (or multiple 50% water-changes every four days) if the nitrate level is above 50 ppm. This will ensure that it does not exceed 25 ppm. 2. One pump of Easy Green for every 10 gallons water. After waiting a few minutes, test the water again. 3. The goal is 50 ppm nitrogen. If the nitrate level is still low, you can repeat Step 2. You will continue to apply fertilizer until it reaches 50 ppm. 4. Wait 3-4 days and test the water again. The water must be changed 50% if the level of nitrate has not dropped below 75 to 100 ppm. Reduce the rate of nitrate accumulation by adding fish to your aquarium or plants that are fast-growing.

Quick dosing with Easy Green all-in-one fertilizer

You should also make sure your plants are not starved if you have too low nitrate. For 10 gallons of water, you should use one pump of Easy Green.

For low light aquariums, you should do once per week. For medium-light aquariums, do twice per week.

If you find that your plant leaves are still developing holes and melting away, a customized dosing method may be needed, based on the nitrate level of the water.

Take down the dates and amounts of Easy Green that were used to fertilize the tank. This will help you figure out your customized dosing schedule. You can decrease the amount of light and/or CO2 injection if you’re having trouble dosing enough fertilizer to meet the nitrate goal. 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.

Take it easy if you notice a nitrate level higher than 0ppm. Nitrate, which is essential for plants, is good. Easy Green was created to be a beginner-friendly fertilizer. You can add one pump to every 10 gallons, and your plants will grow.