from the blog

Controlling Nitrite and Nitrate in the Aquarium

Care and maintenance

September 30, 2020

Left: Nitrite level color chart
Right: Nitrate level color chart

Whether you have a freshwater or saltwater tank, nitrites and nitrates are something you are just going to have to deal with. Both of these substances are by-products of the nitrogen cycle so you can’t avoid having them in your tank but you should do your best to control them. If you let the nitrite or nitrate levels in your tank get out of control, it could have serious consequences for your fish. Luckily, controlling these substances is not a very difficult task – performing a few routine maintenance tasks and installing an EcoBio-Stone in your tank can make a huge difference.

Dangers of High Nitrite/Nitrate Levels

You may already be familiar with the dangers of ammonia poisoning but you may not realize that nitrite and nitrate can be just as dangerous for aquarium fish. In fact, nitrite poisoning is closely linked to ammonia poisoning because high levels of one are often linked to high levels of the other. Nitrite poisoning is often nicknamed “brown blood disease” because it results in increased levels of met hemoglobin in the blood of fish which can cause a brown discoloration. Discoloration of the blood is not the only problem associated with nitrite poisoning – this disease can also cause damage to the gills and inhibits the ability of blood cells to carry oxygen throughout the body. Fish suffering from nitrite poisoning may suffocate, even if the water in the tank has plenty of oxygen in it. Nitrite poisoning can also lead to stress in fish which can increase their susceptibility to disease – secondary infections like fin rot are common in fish that are already suffering from nitrite poisoning.

Though nitrate is less harmful than nitrite and ammonia, it can still be toxic for fish at high levels. The ideal level for nitrate in an aquarium is less than 30ppm, though most fish can tolerate levels up to 50ppm. When the nitrate levels in your tank reach 100ppm or higher, your fish will definitely start to feel the effects. Prolonged exposure to such high nitrate levels may cause increased stress, reduced reproductive capabilities and, in juvenile fish, stunted growth. In addition to affecting your fish, high nitrate levels in the tank could also contribute to increased algae growth. If algae growth is allowed to get out of control, it could have a negative impact on the water quality in your tank.

Tips for Control

As you know, ammonia, nitrite and nitrate are the by-products of the nitrogen cycle. As part of the nitrogen cycle, beneficial bacteria break down organic wastes like uneaten fish food and fish feces. It makes sense, then, that the less waste available in your tank, the lower the levels of ammonia, nitrite and nitrate will be. In order to minimize the amount of waste in your tank, make sure not to feed your fish more than necessary – only offer your fish as much as they can consume in 2 to 3 minutes and remove the uneaten portions of sinking wafers after an hour before they can fully dissolve. Another simple tip for controlling nitrite and nitrate in your tank is to install an EcoBio-Stone. These stones are made from volcanic stone and they are infused with beneficial bacteria as well as the nutrients they need to thrive. Adding extra beneficial bacteria to your tank through the EcoBio-Stone will help to maintain the nitrogen cycle, combatting high nitrite and nitrate levels in your tank. In combination with routine water changes, adding an EcoBio-Stone to your tank is an effective way to keep the water quality in your tank high and the nitrite/nitrate levels under control.