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Methods of Cycling


Yes, it is as it sounds, some people get their system started and cycled by adding urine to the system. Urine contains urea and urea breaks down to ammonia, once you have ammonia this can be a useful source of food for beneficial bacteria populations. It’s a good idea to age your urine for a few days to a week in an open well ventilated area before adding it to the system, but not totally necessary, you can just add straight from the source if you wish. If you are taking any type of medication it’s not recommended that you try this method.

Urea Fertilizers

Another method to add an ammonia source to help establish the beneficial bacteria is to use Urea fertilizer, generally available from agricultural suppliers, hardware stores and nurseries. This is a fairly straightforward method of cycling a system, however you must be careful of your dosing, regular water testing is recommended.


Household ammonia can be sourced from many different places. As with urea, care is required to ensure you don’t overdose the system. Also when sourcing your ammonia make sure that you only use food grade ammonia, there are plenty of cleaning and industrial ammonia sources but they often have perfumes and other additives.

The dead prawn or fish

Yep a method of cycling practiced a fair bit within some aquarium circles over the years. By placing some rotting fish or crustacean in the system you are inducing a source of ammonia for the bacteria to feed on.

Fish feed

You can start cycling a system by introducing the fish feed you will be using to feed the fish into the system, as the feed starts to break down on the bottom of the fish tank and in the growbeds it will release ammonia for the bacteria to feed on.

Feeder fish and/or fingerling

Possibly the simplest method of starting a system and the method we recommend so long as you follow a few simple golden rules. Your system can be cycled by adding feeder fish, usually cheap bronze comets or goldfish to start the system before adding your final fish species. You can also stock the system with fingerling of whatever type of fish you plan on growing in the system and this is the way we start our systems and the method we recommend people start theirs. But feeding the fish must be kept to a strict minimum for the first 2 months. No more than one tablespoon of feed, per day, per 500L of media. If you get an algal bloom, stop feeding until the algae clears. After 2 months you can start increasing feed levels slowly because your bacteria would have been established. You can easily monitor this with a basic freshwater master test kit.