Lets start with some basic facts. Every living thing is composed of only a few primary elements. Other elements are only present in minute trace amounts. The most common organic elements are oxygen, carbon, hydrogen and nitrogen. Together, these atoms form 96.3% of the Human body by weight. There are a handful of other elements that are commonly found in living animals such as sulfur, phosphorus, calcium, sodium, magnesium, and potassium.

These elements compose the building blocks for our organic molecules, like proteins, sugars, fats, and genetic material. These elements also consist of ions needed for common organic processes, like nerve cells communicating with each other or moving muscles.

Bacteria eventually break all of the complex proteins and molecules in a living organism down back to its basic elements. This is part of the cycle of life. Most of the decomposition is done by aerobic (with oxygen) bacteria. The most abundant end products of aerobic bacteria are carbon dioxide, water, nitrates and nitrites, sulfates, and phosphates.  

In nature, plants will use up all or most of the nitrates and phosphates available and then animals eat the plants and the cycle begins again. However, an aquarium is an artificial system and it usually does not have enough plants, if any, to use up the available nitrates and phosphates. Most aquariums also have a higher concentration of fish than is found in nature.

Phosphates are not toxic to fish and other aquarium inhabitants and thus are far less of a problem than nitrates.  They also accumulate much more slowly than nitrates and are less abundant.  However, phosphates can contribute to algae growth.  Most algae need both nitrates and phosphates to grow.  The only exception is cyanobacteria (red slime algae) which does not need nitrate although its growth is severely limited without nitrates.  In other words, eliminating nitrates will eliminate almost all algae problems but you will still want to use some type of chemical phosphate removal system and/or do occasional water changes to keep phosphates under control.

Nitrates are less toxic than ammonia or nitrites, but they are still toxic to humans, animals and fish. The EPA maximum allowable nitrates in tap water is under 10 ppm.  In humans it causes a condition called blue baby syndrome which is a very serious condition that develops in infants exposed to nitrates. It causes a similar condition in livestock and fish.  The condition is caused because organisms tend to convert some of the nitrates back into nitrite which is extremely toxic.  For example check out The EPA Consumer Factsheet on Nitrates.

Fish will definitely feel adverse effects and become more stressed above 40 ppm which is very easy to reach in your average fish tank.  Nitrates are also the primary contributor to unwanted algae growth.

Fortunately there is now a natural, cost effective way to remove the nitrates from your tank using anaerobic (without oxygen) bacteria which breaks down the nitrates into nitrogen gas. Nitrates are much more of a problem than phosphates due to their toxicity and much greater abundance. Remember, it is the fourth most common element in the body.

The most common end products from anaerobic decomposition are carbon dioxide, methane, nitrogen, and hydrogen sulfide, which are all gases.  They will be present in the effluent in small amounts. The methane, nitrogen, and hydrogen sulfide are not very soluble in water, much less so than oxygen and carbon dioxide.  Therefore when the effluent is aerated, all of the methane, nitrogen, and hydrogen sulfide will be released into the atmosphere and replaced with oxygen.  None of these gases are toxic to humans or fish until they are present in very large quantities or in such large quantities as to cause asphyxiation (no oxygen).  

All aquariums inherently have enough water flow to aerate the water as the fish constantly use up oxygen in the water.  If there were not adequate water flow the fish would suffocate.  When the denitrator is used, the oxygen and carbon dioxide in the tank will balance each other out and the methane, nitrogen, and hydrogen sulfide will escape into the atmosphere.  They will not build up or remain in the aquarium.  The nitrates are simply converted to gases that are released into the atmosphere.

The fundamental principles that apply to a denitrator are the exact same principles used by the "Jaubert" or "plenum" filtration method.  These have been successfully used by aquarist for decades to minimize tank maintenance.  The downside to these methods is that they are less effective than a denitrator, complicated to set up and require a very thick substrate which can itself be very costly.  

As you can clearly see, there really aren't any mysterious substances lurking in your fish tank just waiting to kill your fish if you don't change water.  Nitrates are the primary reason to change the water in your aquarium. Everyone has known about the harmful effects of nitrates for years.  Now, you can do something about it.  An Aquaripure denitrator is an economical and effective way to rid your tank of nitrates.  It will be much cheaper and easier to maintain than using chemicals, doing frequent water changes, or setting up a plenum. 

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