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Cycling a Saltwater Aquarium

clownfish in anemone

Cycling a saltwater aquarium requires patience and is the very first test to a successful reef tank. After you have meticulously designed your rock aquascape, added your sand and filled your tank with saltwater you will need to let nature take its course and wait for the biological process to commence. You will hear this often as a beginner, “A saltwater aquarium is all about patience. Nothing good happens fast in reefing.”

What is the “Nitrogen Cycle”

The Nitrogen Cycle is the process of a bacteria breaking down and converting ammonia into nitrite, and then nitrite into nitrate. Ammonia is created by fish waste, fish food, dead livestock and more.

The Nitrogen Cycle
Users Eliashc, Ilmari Karonen on en.wikipedia, Public domain, via Wikimedia Commons

Getting the cycle jump started

In order to start the cycle you will need a bacteria source and an ammonia source. It used to be common practice not too long ago to just toss a cheap disposable fish in a newly setup aquarium and let that fish eat and produce ammonia to start the cycle. Today there are newer methods that do not involve giving a fish a creul and slow death sentence. Ammonia will burn the gills of a fish and cause it to have a hard time breathing, drinking water and eating. We now bottled bacteria such as Microbacter7 and ammonium chloride to add ammonia to the aquarium in low concentrations to get the cycle jump started.

How long does the cycle take?

Generally, the cycle can take anywhere from hours to a month depending on which bacteria you use and how you help the cycle along. You can either use Fritz TurboStart live bacteria and add a fish immediately (which is not creul with this specific bacteria) to basically instantly cycle your tank on day one. Or you can go the more traditional route which is to add Microbacter7 or Dr Tims One and Only bacteria and keep your ammonia elevated by dosing ammonium chloride to around 2-3 ppm. This method normally takes a few weeks to a month to complete the cycle.

Live bacteria vs dormant bacteria

Live Bacteria

Fritz TurboStart is a relitively new bacteria to the market in recent years and it has brought a new way to cycle to the saltwater hobby. Many people have had success with just adding TurboStart to their tank and adding a fish immediately. This bacteria is very alive and works by instantly converting ammonia to nitrite, then nitrate. It must be kept refridegrated and has a shorter shelf life. It is also pretty expensive compared to other dormant bacterias.

Dormant bacteria

There are several dormant bacteria brands on the market that will cycle your aquarium, just not as fast as TurboStart. Some of the more popular dormant bacteria are Microbacter7 and Dr. Tims One and Only. These bacteria take longer to cycle the aquarium due to them being in a dormant state and needing time to reproduce and colonize your rock, sand and filtratrion. To feed these types of bacteria you will need to add ammonium chloride to your tank. After a few weeks or months the cycle will be complete and you can add your first fish.

Tracking the cycle with test kits

If you choose to take the long route by using dormant bacteria you can track the progress of when the cycle is complete by testing regularly for Ammonia, Nitrite and Nitrate. API Saltware test kit has each test you need for a great price. This test is not the most reliable or accurate but it will get the job done. After the cycle is complete you will likely never use this test kit again before it expires, so you really do not need to buy a more expensive test kit. Test every 2-3 days to track the cycle’s progress to know once you can add your first fish.


Cycling a saltwater tank is detrimental to the aquariums overall success. It is the building blocks of the tanks micro biome. It is what keeps fish and other inhabitants alive. Dont rush this process. Throughout these crucial days, weeks and months your tanks bacteria biodiversity will change, grow and shrink. Dont rush it. You cant force nature to go any faster than it wants to. Its can seem like a long process but taking your time is worth it in the end. Afterall, our pets depend on us to get it right for their sake.