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? And if nitrate is so toxic, why do many aquarium plant fertilizers increase nitrate levels when they are made to be safe for fish, shrimp, and snails? Let’s talk about one of the main points of confusion in the aquarium hobby – nitrate.

What is Nitrate, exactly?

The aquarium’s waste is a source of toxic nitrogen compounds, such as ammonia, which can be produced when fish and other animals eat or poop. The ammonia is purified by beneficial bacteria that grows in the fish tank. 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. The Easy Guide to the Nitrogen Cycle in Aquariums has more information.

How to Measure Nitrate

Nitrate cannot be detected by the naked eye since it is both colorless and odorless, so fishkeepers usually measure it using either water test strips or kits that chemically react to the nitrate in the water. Aquarium Co-Op Multi-Test Strips measure nitrate quickly and five other parameters in under a minute. Simply dip a test strip in the aquarium water, such that all the test pads are submerged, and gently swirl it underwater for 3 seconds. You can then remove the test strip from the aquarium water without shaking it off. Keep it horizontal 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 can be used to measure nitrate or other parameters in water.

What are safe levels of nitrate in aquariums?

Ammonia and Nitrite are toxic to some animals, but nitrate is far less toxic. Unfortunately, not enough research has been done on how toxic nitrate can be to all the animals that 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 recommend keeping fish tanks below 80-100 ppm of 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. Live aquarium plants need nitrate to thrive. Fish, shrimp, and snails do not suffer from a lack of it. When nitrate drops to 0-20 ppm, plant leaves can turn yellow or translucent (especially starting at the leaf tips) and eventually melt away because the plant is forced to consume nutrients from its old leaves at the bottom in order to make new leaves at the top. We aim to maintain a minimum of 50 ppm of nitrate in our planted tanks.

Signs indicating a 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. You can reduce nitrate levels quickly and easily by performing a partial waterchange. Take out 30-50% of the old, nitrate-laden water using an aquarium siphon and refill the tank 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. This flow chart will show you how to make water changes.

We know that most people don’t like water changes so let’s explore some ways to keep nitrate levels low. High nitrate is often seen in aquariums with high bioload – meaning that lots of fish poop, dead leaves, leftover food, and other rotting organics are in the water. To reduce nitrate long-term, you can decrease the number of fish and/or the amount of food in your 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. Aquatic plants are a great choice because they consume nitrate naturally, which allows them to grow more roots and leaves. In general, fast-growing plants like water sprite and Pogostemon stellatus are capable of eliminating nitrate at a quicker rate than slow-growing plants like anubias and java fern.

Is fish poop 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. 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.

As you can see in the list of nutrients above, the purpose of Easy Green is to raise nitrate (or nitrogen) and other nutrients so that plants have enough to consume. Because they are macronutrients, your plants require more of them, the percentages for nitrate and phosphate are higher than others. 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 for Aquatic Plants

How do we reach the ideal concentration of nitrate without having too much or too little? You can see that your aquarium is consistently producing nitrate.

Too much nitrate

, you may be tempted to stop using Easy Green since it will further increase 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. Perform a 50% water changing (or multiple 50% water changing every four days) until the nitrate level reaches 25ppm. 2. One pump of Easy Green for every 10 gallons water. Allow the water to cool for at least 24 hours, then test it again. 3. You want to get to 50 ppm nitrate. If nitrate is still too low, repeat Step 2 to keep dosing fertilizer until you reach 50 ppm. 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

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:

Low light aquariums require to be administered once each week. – Dose twice a week for medium light aquariums.

A customized dosing system may be required if you notice that the leaves of your plants are still developing holes and melting. This is based on the water’s nitrate levels.

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 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. Simply add 1 pump for every 10 gallons to your plants and watch them grow.