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How Do I Perform a Fishless Cycle?

Posted in All About the Water

This article describes a method for cycling your tank without harm to fish. If you are not familiar with the Nitrogen Cycle, this article will give you the general information you need.

Basic Needs

You will need pure ammonia or fresh urine.

Hardware, discount & drug stores sell various brands of ammonia.

Finding 100% pure ammonia is sometimes challenging because many brands contain cleaning agents, sudsing agents or perfume, which are unsuitable for aquarium use.

Read the ingredients, use only “Pure Ammonia” or “100% Ammonium Hydroxide”. Chelating agents are OK.

If you are still not sure about the purity of a given bottle of ammonia, try shaking the bottle, pure ammonia will not foam, ACE Hardware, Top Crest & Whirl Clear are reportedly good brands to look for.

You will need accurate test kits. Test kits for NH3(ammonia), NO2(nitrite) & NO3(nitrate) are required, PH is good to have.

Getting Started

Setup the tank, filters with media*, water, heater(s), lighting… Everything ready to go like fish were already at home.

Mature media/substrate may be used to jumpstart the cycle, this will significantly decrease cycling time.

Water must be dechlorinated and any water changes must be dechlor'd.

Any standard conditioner is acceptable, even those that detoxify ammonia, as it is still avaiable to the beneficial bacteria.

Water temp should be between 75'-80' for optimal bacterial growth.

PH should be between 6.5-7.8 for optimal bacterial growth.

How much ammonia to add?

You can easily figure out aprox how much ammonia will be need to attain 3-4ppm in whatever sized tank you have. Simply take a one gallon container and using a dropper (pipette, eye-dropper, etc) add ammonia until desired level is achieved in the container. 3 drops in one gallon, you have a 75 gallon tank, 3×75=150drops.

Convert drops into a useable measurement such as tspns/ml and you can easily dose the tank.

Conversions: 1tspn = 96 drops / 1ml = 19.47drops

Step by Step

Add enough ammonia to attain the 3-4ppm.

Every day you will test for ammonia & nitrite.

When you see the ammonia fall below the 3-4ppm, add enough to bring it back to 3-4ppm.

You will do this until you see a rise in nitrite, this can take days-weeks.

Once nitrite is rising you cut the original amount of ammonia in half, in that you now want to maintain an ammonia level of about 2ppm.

Ammonia should continue to fall despite daily dosage.

Nitrite should continue to rise.

If nitrites go off the test scale it is no cause for concern, do a water change (do not vacuum substrate or clean/rinse the filter(s)) to lower nitrite to a testable level, but being sure to reintroduce ammonia to maintain the 2ppm level.

Daily tests should show ammonia coming down regardless of daily dosage, and nitrite should start coming down too.

Time to start daily testing for NO3(nitrate) as well as ammonia/nitrite.

As nitrite comes down nitrate will go up.

As nitrate goes up, ammonia/nitrite will eventually zero out, despite daily dosing.

Continue daily dosage of ammonia, continue daily testing of NH3, NO2 & NO3 for 2-4days to ensure cycle is complete.

You are now fully cycled, continue daily dosage until you are ready to introduce fish.

The beneficial bacteria must be kept fed or they will die quickly.

Right before you you want to add fish you must do a large water change to reduce nitrates, I suggest at least 75-90%.

Immediately after this water change you should add fish, remember to double check temp/PH before adding the fish, adjust water or acclimate fish as necessary.

I suggest starting with a moderate stock level and feeding schedule for the first week, then adding fish slowly.

Written by: ChileRelleno.