Cycling a New System Using UREA

The use of UREA as a method of cycling a system should be done with caution. Steady as she goes.
Use very small amounts. Some members have got into a real mess by getting heavy handed with the UREA.
If you must use UREA in your new Aquaponics system...just once only....half a teaspoon...then a CAP full of Seasol daily after that. (Seasol is a seaweed extract commonly available in plant nursery shops)
Plant your plants immediately.
After about two weeks...get the fish.
Assuming you are getting fingerlings..not large fish.

Plants will use directly some of the ammonia produced by the fish, so it is good insurance for the fish to have plants into the system right from day one. The plants will do very well on the Seasol. There is very little ammonia producing elements in Seasol, but there is enough there to get the good bacteria going.
As the plants grow they are more and more capable of directly taking up ammonia produced by the fish.

Be patient, in the dead of winter it could take 4 to 6 weeks to get a nitrate reading. Don't be tempted to "give it a bit more" to try and hurry everything along.

To convert the UREA to a usable form of Ammonia an enzyme contained within a specific bacteria is needed, (urease) that is found in soil but rarely found in a new aquaponics system. This is one of the reasons why people get varying results when attempting to cycle with urea.
It also explains why repeated use of urea in regular dirt gardens (and new aquaponic systems) has ever diminishing results, and why leaf burn occurs because the enzyme needed to convert is either not available or not available in sufficiency quantities.

Urease is an enzyme that catalyzes the conversion of urea to ammonia and carbon dioxide. Certain bacteria that convert urea to ammonia as part of the nitrogen cycle contain this enzyme.

The conversion of urea and water into ammonia and carbon dioxide, one of many biochemical reactions catalyzed by enzymes.
Ammonia changes it's state when passing through Ph 7 making it either toxic or less toxic to fish.

For this reason it is very important to keep control of the pH in a new system. Ammonia is much more toxic to fish at pH 7 or above.

Much more attention should be paid to pH management than anything else. If your system is above 7 pH then even small amounts of ammonia will be a threat to your fish.

So when cycling your system make sure you test for pH daily and take steps to get it to 7 or just below before you introduce your fish to your new system.

Posted By Murray Hallam on 12th December 2011

Updated : 4th October 2013 | Words : 454 | Views : 3230 | Comments : 2

Posted By Steve McKenzie on Tuesday 25th March 2014 @ 10:55:41

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