Nitrites Mar

Nitrites in Marine Aquarium Systems

By James Gasta

What Are Nitrites, How Do They Form?

Nitrites (NO2) are the second stage in the nitrogen cycle. Nitrifying bacteria are readily available in the aquarium and will colonize as soon as a nutrient source (ammonia) becomes available.

While ammonia is converted by bacteria called Nitrosomonas, Nitrobacteria is responsible for converting nitrite into nitrate. Nitrate is the least toxic product of the nitrogen cycle and some sensitive species of fish, such as Butterflyfish will show signs of stress at nitrate levels exceeding 25ppm.

When new aquariums are set up, nitrogenous compounds in the form of ammonia will rise to high levels. This provides a food source for the bacteria to form a colony and start the conversion process or nitrogen cycle. Both Nitrosomonas and nitrobacteria are aerobic bacteria and require a constant flow of oxygen in order to survive and perform their duties.

Can I Speed Up The Nitrification Process?

There are many 'live bacteria' products on the market today, but the problem here is that there is simply too much snake oil in this hobby that has no self policing agency or standards upon which you can rely. Before buying a product, it is suggested that you read buyer's reviews and/or product reviews before making your purchase. However, I can recommend one product that does truly work, the product is Dr. Tim's One and Only Nitrifying Bacteria developed by Dr. Timothy Hovanec, who for 17 years was the Chief Science Officer of Aquaria Inc. A reference to fishless cycling can be found in the footer.

What Is A Safe Level To Keep Nitrites At?

Nitrite levels should be undetectable after the tank has completed the nitrogen cycle. Although not as dangerous as ammonia, nitrite is still a toxic chemical and can cause stress for fish even at levels as low as 0.5ppm. Levels exceeding 10ppm can be lethal over a period of time. Continued high nitrite levels of seven days or more can destroy the hemoglobin or oxygen carrying cells of the fish and other animal life in the aquarium.

What Can Cause Detectable Nitrites After The Tank Has Cycled?

Detecting nitrites after the tank has cycled can be caused by the biological filter not working properly due to lack of water flow and/or oxygen, or the tank is overstocked beyond the handling capacity of the nitrifying bacteria.

What Can I Do To Prevent Detectable Nitrites?

Providing good water flow and surface movement is all that is necessary as long as there is enough area for the nitrifying bacteria to colonize. This can be in the form of live rock or biological media such as bioballs. If you live in an area where frequent power outages occur, it is recommended that you have some type of emergency battery operated power head to provide flow and oxygen to the nitrifying bacteria or biological filter.

Should I Routinely Test For Nitrite Even Though My Tank Has Cycled?

Nitrite should be monitored if you have a power outage for a significant period of time, or after you have added new livestock. The addition of new livestock may cause nitrites to rise slightly but will soon return to zero once the bacteria have adjusted for the increased bio-load and providing you have not exceeded the stocking level of the aquarium.

Further reading:

http://www.wetwebmedia.com/marine/setup/filtration/biological/biofiltr.htm http://www.wetwebmedia.com/estbiofiltmar.htm http://www.wetwebmedia.com/marine/setup/filtration/marineFiltr.htm http://www.wetwebmedia.com/marine/setup/filtration/biological/biofiltr.htm

http://www.drtimsaquatics.com/fishless/fishless.html

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