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Cycling a New Aquaponics System. Quick Guide

How to Cycle a new Aquaponics System.
Have your system built and the water circulating, the auto siphons are functioning and adjusted well. If you have decided to use a timer system for flood and drain, then your timed cycles should be functioning well. You have run the system long enough for the water to be clearing. The water can be a bit dirty from loose dust on the clay pebbles or gravel, but it should start to clear after a few days.

Barra in a basket

Small Barramundi contained in a plastic laundry basket within the fish tank. This makes it easy to take the fish out and treat them in a salt bath if necessary.

Small Barramundi contained in a plastic laundry basket within the fish tank. This makes it easy to take the fish out and treat them in a salt bath if necessary.

Adjust the pH to just below pH 7. Adjust using pool acid to bring pH down or hydrated lime to adjust pH up. Get some plants in there right away. The plants will soon tell you if there is not enough nutrients. Use some Maxicrop or Seasol seaweed extract to provide some nutrient for the plants. It will not harm the fish once you have them in the system.
There are very small amounts of ammonia in these products, so the process of building a suitable colony of beneficial bacteria will be slow, but it is a very safe and gentle way of cycling your system. Be patient. These are natural processes and they take time. If you feel you must speed the process, then, in addition to the seaweed extract, add a VERY SMALL amount of Urea. No more than 1 teaspoon per 1000 litres of water.
If you can obtain some pure ammonia then use that in preference to Urea. Once again, very a small amount like 1 tablespoon per 1000 litres (250 gallons). I stress that my preference is not to use Urea. It can be vicious and cause lots of problems if overused.

The beneficial bacteria are naturally occurring, and they will begin to multiply once there is ammonia present. One option t ensure you have a good number of the beneficial bacteria present is to add some water, 3 or 4 liters (1 gallon) from a disease free freshwater aquarium, or a friends Aquaponics system. The beneficial bacteria will be in this water and will take up residence in your new system and begin to multiply and use/process the ammonia. After your system has been running for about two weeks and everything is going nicely... add the fish of your choice.

Stock lightly for your first batch of fish. Don’t be tempted to have a lot of fish in the beginning. Remember , loads of aeration and a backup system. Conduct your usual tests for Ammonia, Nitrites, Nitrates at the following frequency. Daily for pH and Ammonia. Every second day for Nitrites. When the Nitrites appear you will know that the beneficial bacteria are on the increase. A short period of time after that Nitrates should start to appear. Test for Nitrates every second day until you see them appearing. Once you see Nitrates you know that your system has cycled. All the while test for Ammonia. If it goes beyond 1.0 mg/L then carry out a one-third water change.
The good thing about having the plants in is they are capable of taking up some of the ammonia. Once the system has completed the "cycling" process tests for ammonia should reveal very small amounts or even none at all on occasion. All the while test pH. Try to keep it just below pH 7. It is not uncommon to observe swings in pH during this early period. Don’t panic and start chasing the pH. Only adjust when you see a firm pattern developing, for example, if it stays at say, 8.0 for 3 days, adjust gradually down using pool acid or similar…….be gentle, adjust in small increments, until you get it steady just below pH 7.

Once your system is up and running and everything is just fine, if you want to introduce more new fish always quarantine them in a salt bath for a week before putting them into your main system. Don’t risk bringing sick or infected fish into your working Aquaponics system.
Happy Aquaponics Murray.

Posted By Murray Hallam on 29th April 2015

Updated : 21st May 2015 | Words : 737 | Views : 4437 | Comments : 19

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What is the minimal allowance for the temperature to establish beneficial bacteria?

Posted By Ziad Algorashi on Monday 18th December 2017 @ 15:26:23


It works best at around 23c but can work down as low as 12c. It is difficult to get a system to completely cycle at low temps.

Posted By Murray on Monday 18th December 2017 @ 15:26:23


Murray, your the reason I got into aquaponics. Thank you. Joe in central Fl. If your ever back in the area email me and come by . I'm very close to green acres and Morningstar fisheries. [email protected]

Posted By Joe on Monday 31st August 2015 @ 02:21:52


Thanks Joe,
I will be over that way in March 2016. So, love to meet then.
Hope all is well with you.


Posted By Murray on Monday 31st August 2015 @ 02:21:52


Hi Murray - Still following your exploits. Pls clarify the "salt bath for a week". Won't that kill the fish? Cheers, Guy

Posted By Guy Biddlecombe on Thursday 21st May 2015 @ 13:46:54


Hi Guy,
No it will not. All freshwater species I have worked with are very salt tolerant and do well with salt treatments. I am quick to caution that may not be the case with every single freshwater species out there in the world. For example, I would be cautious in using salt with Trout. I have not kept Trout but hope I am fortunate enough to get some one of these days.

Posted By Murray on Thursday 21st May 2015 @ 13:46:54


Thx! reliable informations as always!

Posted By Tomek on Thursday 21st May 2015 @ 07:26:42


Thanks Tomek.

Posted By Murray on Thursday 21st May 2015 @ 07:26:42


Hi Murray,
I have learned so much from this website, especially about the 3 nutrients missing that need to be added. Iron, potassium and calcium. Your videos show how to add the first 2, but what type of calcium do we need to use and how much?

Posted By johan snijder on Wednesday 4th December 2013 @ 07:28:24


Hi Johan,
Calcium is added when there is a need to buffer the pH. By using hydrated lime to buffer the pH upwards calcium is also taken care of. Hydrated lime is very high in Calcium. I hope this helps. Regards Murray

Posted By Murray on Wednesday 4th December 2013 @ 07:28:24


Hi Murray,
I am just filling my system, 4500 lts, and would like to know your views on using a Koi Carp instant bacteria, it seems get get good reviews from the fishy people but nothing on the aquaponics front.
Thanks for all your help so far, Cheers, Simon, London

Posted By simon walters on Sunday 28th April 2013 @ 15:19:12


Hi Simon, Ok if you want to but really unnecessary. The beneficial bacteria are naturally occurring and will come if the right conditions are there.

Posted By Murray on Sunday 28th April 2013 @ 15:19:12


I am starting my aquaponic first time.in the growbed i am fitting the drainpipe just one inch below from top.so the gravels immers in water all time. so please tell me how i can fix the drainpipe.

Posted By abdul jabbar on Monday 4th March 2013 @ 08:36:46


Hello Mr. Hallam, I have had standard gardens forever but wanted to start an aquaponics system. I have been doing research and gathering information for over a month. Got onto this blog about an hour, maybe hour and a half and learned more practical info than I did the whole previous month. I want to thank you for this. Hope to have an operational, (small scale) system up and running by early May. I'll be back...

Posted By peter vangoethem on Tuesday 19th February 2013 @ 16:16:14


You are welcome Peter, I am glad you found value in my website.

Posted By Murray on Tuesday 19th February 2013 @ 16:16:14


Would a fish emulsion like charlie carp work instead of Seasol?
Its organic, sustainable, and my other plants love it.

Posted By Alex Gribbin on Tuesday 12th February 2013 @ 13:13:40


Yes Charlie Carp is fine but go steady with it.

Posted By Murray on Tuesday 12th February 2013 @ 13:13:40


Hello Murray, I was wondering if the Seasol or Maxicrop for here in the states are harmful to fish. I have some starter goldfish and wanted to add Maxicrop this weekend. I am using a 330g Fish tank with a max capacity 175G sump tank (I keep the sump at 125G). The goldfish are kept in the sump tank since I am using your CHOP 2 configuration and don't wish to actually raise Goldfish. Thank you and I love your videos.

Posted By Robert Montoya on Thursday 7th February 2013 @ 21:29:12


Hi Robert,
Many use Maxicrop with good success in their home Aquaponics systems.

Posted By Murray on Thursday 7th February 2013 @ 21:29:12


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