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.
- 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.