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? 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. The beneficial bacteria also produces a number of end products, including


. 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

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 submerge a test strip into the aquarium water and swirl it underwater for three 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 are used to measure nitrate and other parameters.

What are Safe Levels of Nitrate in Aquariums?

Ammonia and Nitrite are toxic to some animals, but nitrate is far less toxic. It is not known how toxic nitrate really is for all species of animals that can be kept in aquariums. To give you an idea of the situation, a paper on Nitrate toxicity to aquatic animals reported that nitrate concentrations rose to 800 ppm just before becoming fatal to guppy eggs. 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. 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 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

If you have a fish tank that is heavily stocked with animals or does not have a lot of aquarium plants, the nitrate level produced by fish waste can naturally climb to 80-100 ppm and above. You can reduce nitrate levels quickly and easily by performing a partial waterchange. Use an aquarium siphon to remove 30-50% of the old, nitrate-laden liquid and then refill the tank with clean, fresh water. In general, it is best to not shock fish with large water changes. For example, if the nitrate content in your tank is greater than 100ppm, then you will need to make multiple water changes 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. The best ways to reduce nitrate over the long-term are to decrease the amount of fish and/or food that is put 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.stellatus and water sprite, which are fast-growing, can eliminate nitrate faster than slow-growing plants like anubias.

Is Fish Poop a Good Enough Fertilizer for Aquarium Plants?

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


There are many nutrients that plants require in high quantities, such as potassium, phosphorous, nitrogen and phosphorous.


These nutrients are essential for plants and can be found in trace quantities (such as iron boron and manganese). 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. If beginners attempt to grow plants without fertilizer, they often experience serious nutritional deficiencies within a matter months. Easy Green was created to address this problem. It is an all-in-one fertilizer that helps keep plants healthy.

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. The percentages of potassium, phosphate and nitrate are actually higher than the rest, because these macronutrients are more important for plants. Easy Green will cause an increase in nitrate if added to water. This can be measured using a test strip or kit. The goal is to add enough Easy Green to reach 50 ppm.

How to keep the right amount of Nitrate in 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

Easy Green may cause a rise in nitrate so you might be tempted not to use it anymore. Withholding fertilizer could result in plants being deficient in other nutrients, as well as 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. Do 10 gallons of water with 1 pump of Easy Green. Allow the water to cool for at least 24 hours, then test it again. 3. Your goal is to achieve 50 ppm of nitrate. If the nitrate remains too low, continue with Step 2 until it reaches 50ppm. 4. Then wait 3-4 days before testing the water 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 using Easy Green all-in one fertilizer

On the other hand, if your planted tank always has too little nitrate, you should regularly dose fertilizer to avoid starving your plants. For 10 gallons of water, you should use one pump of Easy Green.

Low light aquariums require to be administered once each week. Medium light aquariums require twice each week.

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 have trouble doseing enough fertilizer, decrease the lighting or CO2 injection. Then 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.

The bottom line is don’t be alarmed if your nitrate readings are higher than 0. Nitrate is good and even necessary 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. Add 1 pump to 10 gallons of water and watch your plants grow.