The Nitrogen Cycle

Cycling the tank.

My Saltwater Aquarium : The Nitrogen Cycle

By Reef Ace

In this article I will take the tank and equipment I selected in my article: My Saltwater Aquarium : Simple setup and explain how I put it all together and completed the Nitrogen cycle.

Putting it together.


Aquascaping is how I arrange my sand and rocks to create my desired appearance in the tank. I found that aquascaping is best done before filling the tank with water.

When aquascaping I made caves where my fish could hide if they felt stressed by other fish or their new environment. I also avoided placing rocks too close to the glass of the tank, leaving enough space so I am able to clean algae off the glass during tank maintenance.


First consideration is the water I will be using in my tank, it can not be direct tap water because tap water contains too many harmful dissolved solids that will kill my marine fish and corals. The good news is that I have several good ways to solve this problem.

1) RO/DI filter system ( Reverse Osmosis De-Ionized water )

2) Ready to use boxed water with sea salt mix added (sold at the aquarium store)

3) Water filter system that removes all dissolved solids from tap water and a TDS meter (an inexpensive and convenient digital tool to instantly check your overall water quality. TDS = Total Dissolved Solids )

For the initial fill of my 13.5 gallons tank, I bought boxes of pre-mixed sea salt and water from my aquarium store. If I needed to filter a larger amount of water I may have setup an RO/DI filter system.

Starting my filter.

My tank had a build in filter system and powerhead , it also came with some bio media and a sponge.

This system circulates the water creating flow which adds oxygen to the water, while filtering out fish waste and uneaten food to create and maintain an environment where beneficial bacteria can multiply and keep my tank clean.


This was the prefect  time to add my thermometer keeping the temperature at 78 degrees, testing my lighting and set my timer.

Cycling the tank.

The term refers to the Nitrogen cycle, a process where the nitrosoma bacteria, start building up in your aquarium breaking down harmful ammonia (NH3) created by fish waste and uneaten food, into nitrite (NO2) which is then broken down further by nitrobacter bacteria into nitrate (NO3) which is less harmful. Then nitrates are removed during tank maintenance with water changes.

I used live sand and rocks to aid the cycling process because it already contain the beneficial bacteria giving my tank a kick start. I also used products with a dose of nitrifying bacteria sold at aquarium stores to help cycle my tank.

Saltwater testing kits helped me follow the process. First I saw a spike in ammonia concentration, jumping from zero to a higher number. This was followed by a spike in nitrite, follow by a spike in nitrate. After my nitrate went up, my nitrite and ammonia level fell back down to zero indicating the completion of the cycling process making my tank ready for live stock.

The cycling process takes about 4-6 weeks. This is an extremely important step during setup and rushing it may cause loss of fish or corals. Test, test and test before putting live stock in.

During the cycling process I took that time to research and decide what fish and corals I could to put in my tank. Notice how I didn’t say “the fish I wanted to put” but rather “the fish I could put in the tank” small setups have limits. But that didn’t stop me because nature creates beautiful and cool marine life and corals for small tanks too also I need decided on a clean up crew.

Follow me to find out what fish and corals I put in the tank plus I will answer the questions, what is clean up crew? and why do I need them?  

My Saltwater Aquarium :  Putting Fish In.

Disclaimer: This article is intended to provide my personal experiences as I setup my saltwater aquarium tank for entertainment purposes only. I am not a professional in this field. I have gained my knowledge and methods as explained in this article by my own personal experiences and research. Before setting up an aquarium tank or following any of my methods please research, seek professional advice and decide for yourself if it is right for you.

Please follow me, your support is needed and greatly appreciated. Thank you.

What Drives Me

My Mission

My mission is to never stop learning and sharing  my experiences and love of fish keeping

Love Thy reef




Anemones are beautiful living creatures.


Share your knowledge.

keep on dreaming

Dream big , often and follow your dreams.


Love all 

support each otheR

Inspire others to grow.

Corals are beautiful