Culturing Bacteria
The fishless cycling method is the safest for growing beneficial bacteria without putting fish through unnecessary toxic conditions or stresses that all new tanks experience after they are set up. A fishless cycle enables an aquarium to be stocked fully the moment the cycle is declared complete. Yes, you are able to add quite a load of fish at that time, but ONLY once the cycle has completed. We still recommend you throttle how you add your fish stocks to new aquariums, as there are other factors to consider. Now, how to do a fishless cycle…
What Do I Need?
You simply need a complete test kit for pH, Ammonia, Nitrites, and Nitrates. You also need a source of Ammonia. A liquid bottle of Ammonia from a hardware store is fine. No surfactants, no smells—plain Ammonia is what you need.
What Is Required of Me?
Like making a fire, you start small, and the fire builds itself once it gets started. You will be growing bacteria in a similar fashion. The objective is to keep Ammonia (food for bacteria) dosed regularly and consistently while the beneficial bacteria grow, colonize, and thrive as part of the nitrogen ecosystem. As levels rise and fall, you will adjust accordingly until the cycle is completed. You will need to test regularly and be on the lookout for all the signs of a fishless cycle:
The Basic Fishless Cycle:
At the start, dose 4 ppm Ammonia and keep it sustained for several weeks until Nitrites are detected. Once Nitrites show up on test results, you can throttle back the Ammonia dosage to only 1 ppm. Continue this until Nitrates are detected. Once Ammonia and Nitrites drop to 0 within approximately 12 hours of adding Ammonia, you can consider your aquarium to be in a cycled state.
Essentially, in a matter of hours (usually 12 or so), ALL Ammonia is quickly converted to Nitrites and then into Nitrates. Nitrates will accumulate from then on, and you will need to do a water change to keep Nitrates under 40 ppm. Continue dosing 1 ppm until the night before stocking fish.
Literally, it is this simple to cycle. The hard part seems to be the discipline it takes to test daily, keep Ammonia levels where they need to be, and patiently wait out the cycle. It takes about 6 weeks.
Okay, it’s not much like a fire unless you think of it as a very slow-starting fire. Once these bacteria get going, though, it’s amazing in terms of the growth you will see. A 1 ppm dosed tank is almost the equivalent of a tank’s full stocking. Meaning you now have enough bacteria capable of meeting the demands of a fully stocked tank.
Tens of trillions of bacteria are now working in full force to keep your aquarium safe for fish to live in over the long term. It may even seem like an endeavor, but when was the last time you cultured bacteria and verified the process by testing its effects on toxic chemicals? Be proud—this is scientist stuff that you just pulled off! Congrats! 🙂
Speeding Up the Process
Because the science of growing bacteria is specific and reliable, there are ways to speed up fishless cycling.
- Cloning a Tank:
Take the entire filter system out of a good, cycled tank and move it to a new tank. This is called cloning. Add fish that match its bioload capacity, and you’re ready to go! Be sure to test to verify that the cycled filtration system can handle at least 1 ppm of Ammonia for a day or two. - Using Biomedia:
Transfer biomedia (like a sponge or ceramic bio bag) from an established tank to your new tank. This introduces a significant population of beneficial bacteria, which can reduce cycling time. - Bottled Bacteria Products:
Use a bottled bacterial additive. Be sure to choose products with the correct species of bacteria for cycling. - Freshwater Naturalist Secret:
Use fresh, moist potting soil! The beneficial bacteria in potting soil can jumpstart your cycle. After brushing most of the dirt off your hands, rinse them in your tank. Any small particles left will introduce bacteria to your filtration system, helping colonies grow.
After Completing a Fishless Cycle
Keep the bacteria fed until you add fish. Test how robust your cycle is by increasing Ammonia from 1 ppm to 2 ppm. If Ammonia and Nitrites still drop to 0 within 12 hours, your tank is fully cycled. When stocking fish, ensure the tank has 0 Ammonia, 0 Nitrite, and no more than 20 ppm Nitrate.
If you plan on keeping plants, introduce them during the cycling process. This gives them a 6-week head start to establish roots without interference from fish.