Everything You Need To Know About Nitrate Levels In A Saltwater Aquarium

Last Updated on January 24, 2022 by Marco C.

Have you noticed increased nitrate levels and now want to solve this problem? Click and find out all about nitrate levels in a saltwater aquarium.

No saltwater aquarium would be possible without a nitrogen cycle. Aquarium pets produce toxic ammonia which eventually converts to less toxic nitrogen compounds such as nitrate. After all, nitrates themselves are not welcome in aquarium communities as well, as most aquatic animals consider them toxic.

If you want to avoid all situations that can have negative consequences, keep reading to learn more about ideal nitrate levels in a saltwater aquarium.

What Are The Sources Of Nitrates?

Nitrates come from ammonia which is formed as a product of numerous biological processes that take place in your aquarium tanks. The main source of ammonia is biological waste, such as rotten food, and decaying biological material such as dead fish and invertebrates.

Bacteria in your aquarium tank convert ammonia into less toxic nitrites and then into much less toxic nitrates. Accordingly, you do not need to panic, very low amounts of nitrate may not cause problems.

What Should Nitrate Levels Be In Saltwater Tank?

Although its presence in small quantities is not terrible, it becomes harmful to fish and invertebrates only if it is allowed to accumulate for prolonged periods of time. Keep reading to find out what are the acceptable nitrate levels in a saltwater aquarium.

Saltwater pets are much easier to cope with high nitrite levels compared to freshwater ones. Accordingly, the recommended nitrate levels in saltwater aquarium (fish-only aquarium) are between 10 and 40 PPM (parts per million). On the other hand, when we talk about safe nitrate levels in a saltwater aquarium that contain invertebrates and corals, they are 2 PPM.

Aquariums containing invertebrates must pay special attention to nitrate levels because these animals are generally delicate and therefore sensitive to contaminants. Some specimens could tolerate levels above 5 ppm, but for most anemones and corals such levels would be too high and potentially lethal.

More About Nitrate Levels In A Saltwater Aquarium

In addition, some aquarium hobbyists deliberately increase nitrate levels to improve coral coloration. This is a topic that could be discussed for days, but the vast majorities think it is the wrong way. A much better option is to maintain the correct phosphate to nitrate ratio (Redfield ratio).

some aquarium hobbyists deliberately increase nitrate levels to improve coral coloration

Accordingly, the phosphate content in the reef reservoir should be significantly higher than the nitrate content to avoid color bleaching. *Keep in mind that high phosphate levels can encourage algae growth.

In addition, some fish may tolerate high nitrates in a saltwater aquarium, but prolonged exposure has a significant effect on their health and can shorten their lifespan. At first glance, everything may seem fine, but in fact, there are side effects such as slow growth and a weakened immune system, which can, unfortunately, have fatal consequences.

Damage caused by high concentrations of nitrate in saltwater aquariums is called nitrate toxicosis.

The Best Methods To Reduce Nitrate Levels In Your Saltwater Aquarium

There are several methods to control nitrate in your aquarium. Read more about each below.

Mangrove Plants

This method has been a favorite among aquarium hobbyists for years. Putting mangrove plants in your aquarium is a great way to deal with high levels of nitrate without chemicals or any additives.

Food Offering

Moderate feeding can greatly reduce nitrate levels in your aquarium. Therefore, it is very important to pay attention to the amount of food you give the fish per feeding and on the frequency as well.

Accordingly, try to avoid overfeeding and don’t overcrowd the tank with aquarium pets.

Protein Skimmer

A protein skimmer is an important aspect that allows your aquarium to function properly as it collects and eliminates organic compounds before they break down into nitrates. It has the ability to indirectly reduce nitrates in systems that are more sensitive to pollutants such as coral reef aquariums.

Note that its size must correspond to the volume of water in the tank.

Read more about Protein Skimmers For Saltwater Aquariums.

Filtration Setups (Natural Nitrate Reduction)

The principle of natural nitrate reduction filtration is quite simple and includes nitrifying bacteria that do all the work for you. The three basic settings are live rock, live sand, and a combination of both (live rock and live sand).

Water Changes

Regular water changes are essential for the health, growth, and development of your aquatic pets. It is important to remember that excessive changes in the amount of water in the aquarium at one time are not recommended, as they can lead to shock and potential death.

Try to change a maximum of 50% per weekly session to avoid affecting water parameters. It would be even better if you could make multiple water changes of 15% of the total water volume, an hour or two apart.

When done correctly, partial water change is an effective method for lowering nitrate levels in saltwater aquariums.

Organic Carbon & Vodka

Have you ever heard of a method of “vodka dosing” to lower nitrate levels in a fish tank? This is a new and effective method to solve this problem.

Namely, the method is based on bacteria that are given a source of organic carbon (vodka or vinegar) which they use up by colonizing the entire saltwater aquarium tank. The process is exponential, as the colony grows, nitrate levels decrease.

Keep in mind that nitrates are not exported from the aquarium system, but are converted into bacterial biomass that eventually needs to be physically removed.

To Wrap Things Up

Increased nitrate levels in a saltwater aquarium are problems faced by almost all aquarium hobbyists. Accordingly, you don’t need to panic. By combining the above methods of lowering nitrate levels in your fish tank, you can avoid the possibility of nitrate poisoning.

After all, maintaining your saltwater aquarium is not demanding once you get basic procedures such as proper nitrate level control.

We hope you found this article “Everything you need to know about nitrate levels in a saltwater aquarium” useful. Leave a comment below if you have questions.

Learn more about: How To Reduce Nitrites In An Aquarium