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Nitrification and denitrification are crucial processes in maintaining water quality within a marine aquarium. They are responsible for converting harmful nitrogenous waste compounds, such as ammonia and nitrite, into less toxic forms. Here's a detailed explanation of each process:


Nitrification is a two-step aerobic process that occurs in the aquarium's biological filter, primarily in the presence of beneficial bacteria. These bacteria convert toxic ammonia (NH3) and nitrite (NO2-) into relatively harmless nitrate (NO3-). The two steps involved in nitrification are:

a. Ammonia Oxidation: Ammonia-oxidizing bacteria (AOB), such as Nitrosomonas, convert ammonia into nitrite. This process is known as ammonia oxidation or ammonification and is represented by the following equation: 2 NH3 + 3 O2 → 2 NO2- + 2 H+ + 2 H2O

b. Nitrite Oxidation: Nitrite-oxidizing bacteria (NOB), such as Nitrobacter, further oxidize nitrite into nitrate. This step is called nitrite oxidation and is represented by the following equation: 2 NO2- + O2 → 2 NO3-

The nitrification process is essential for maintaining low levels of ammonia and nitrite, which can be highly toxic to fish and other aquarium inhabitants.


Denitrification is a biological process that occurs under anaerobic conditions, primarily in the substrate or in areas with limited oxygen availability within the aquarium. Denitrification helps reduce nitrate levels by converting nitrate (NO3-) into nitrogen gas (N2), which is released into the atmosphere. Denitrification involves several steps carried out by different groups of bacteria:

a. Nitrate Reduction: Nitrate-reducing bacteria (NRB) convert nitrate into nitrite, nitric oxide, and eventually nitrogen gas. The process can be represented by the following equation: 2 NO3- → 2 NO2- + O2 (nitrate reduction)

b. Nitrite Reduction: Nitrite is further reduced to nitric oxide (NO), nitrous oxide (N2O), and eventually nitrogen gas (N2). The equation for nitrite reduction is: 2 NO2- → 2 NO + O2 (nitrite reduction)

c. Nitric Oxide Reduction: Nitric oxide is reduced to nitrous oxide by nitric oxide-reducing bacteria. The equation for this step is: 2 NO + 2 H+ → N2O + H2O (nitric oxide reduction)

d. Nitrous Oxide Reduction: Nitrous oxide is finally reduced to nitrogen gas by nitrous oxide-reducing bacteria, represented by the equation: 2 N2O → 2 N2 + O2 (nitrous oxide reduction)

It's worth noting that denitrification occurs in areas of low oxygen concentration, such as deep within the substrate, dead spots, or within specialized anaerobic filter media.

In a marine aquarium, it is crucial to maintain a balance between nitrification and denitrification processes. This can be achieved by providing adequate surface area for beneficial bacteria colonization, proper oxygenation, and ensuring areas with limited oxygen for denitrification to take place. Regular monitoring of water parameters such as ammonia, nitrite, and nitrate levels is essential to ensure the overall health and well-being of the aquarium inhabitants.


Future fishkeepers at play.

Bring the kids. We've got you covered.

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Published on Categories General

A long time coming, but Just Fish/Pass Road Pet Center, after decades at 1939 Pass Road, is moving to a new location, just up the street at 2306 Pass Road. A larger, more modern building, and plenty of (paved) parking available!

Before the amazing transformation...

We'll always remember the old store and the many memories and friends we first made there.

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I figure it's time I put thoughts to keyboard in a feeble attempt to relay my feelings about Facebook, the internet etc.

So, when I initiated a Facebook group page, I figured it would be a place for some of the regulars to have a common interest point and more important, get questions answered when the shop was closed by either myself or one of the many knowledgeable folks who frequent the store. Never did I think it would attract almost 400 hobbyists as of this writing, nor did I anticipate the amount of questions and input we would get. Of course as the numbers of participants grow, the more diverse the discussions and inputs.

I appreciate all the patriot missiles that my loyal followers fire off to protect my business and their FFLFS (favorite freaking local fish store), I think its awesome and sometimes its needed. But at the end of the day if we wanna attract more folks to our group we must relax when we see others post up where or what they bought. We don't have it all , and some things I can't even get.

On that note, I will say we would always like the opportunity to get you an item you are considering, that I do not carry, or maybe better yet, have the chance to tell you why we do not carry that product.

Few places can tout their experience of being around for nearly 40 years. I get to see a lot of fish, products, and, unfortunately, people's fails as well as all the successes. It is for that fact that I have some ideas I have determined are best.

We will always be true to one goal: Treat you the customer as we would want to be treated.

If this is a value to you, then maybe when you have a choice between internet or us, you will choose to help us stick around another 40 years; if not, it's OK, as we will still attempt to follow the goal.

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