Originally Posted by Merrilyn
Hi Dee. I've been meaning to write a comprehensive article on Fishless Cycling for some time now, so I guess this is a good time.
First, a few basic things that need to be understood.
The bacteria colony in your bio filter is a living thing. To survive it needs two things. Oxygen and food. The bacteria colony will grow and multiply till it has consumed all the available food, and then the population will remain static. Ammonia is simply a food for the bacteria, so in other words, by adding ammonia in any form to the tank, we are simply feeding the bacteria. If we stop feeding the bacteria, they will gradually die till they are all gone.
Now to begin your fishless cycle, you need to obtain a source of bacteria. For this, you can use plants, gravel or used filter floss from an existing tank. You are simply taking a small colony, and feeding it well, so that it grows and multiplies into a large colony.
So, on day one, fill your tank with tap water BUT DO NOT ADD DECHLORINATOR. Some of the dechlorinators remove ammonia from the water, and that is the very thing that we're trying to add. Simply let the water age for a day or two, so the chlorine dissipates into the air.
Day two, set up your tank, with gravel plants, filter, heater, decorations, driftwood etc and your starter bacteria colony. At the same time, add your food, in the form of liquid ammonia. The amount you add will depend on the strength of the ammonia, but you are aiming for a reading of 5 ppm on your ammonia test kit. That's enough food to give you a good size bacteria colony, which would cope with a full fish load of around 10 adult fish.
Do daily ammonia tests, remember we are aiming for a reading of 5 ppm. As the bacteria colony begin to grow, they will consume some of the ammonia and convert it into nitrite. As you see the ammonia level drop, add a little more ammonia to bring the reading up to 5 ppm again. If you added too much, don't worry, it's just food, and the bacteria will eventually consume it.
After about a week, you should be getting a reading of nitrite as well as the ammonia. That means the colony is growing, which is just what we want. Keep feeding the bacteria, and keep your ammonia reading up to 5 ppm. Some time during the second week, you'll begin to detect a reading of nitrate as well as nitrite. This is the second step in your bio filtration. It takes time for the two different type of bacteria to grow. The first type turns ammonia into nitrite, and the second type turns nitrite into nitrate.
Our aim therefore is to have the ammonia converted into nitrite and then nitrate within a 24 hour period. How quickly this happens, will depend on the size of the bacteria colony you first introduced into the tank at the beginning of the cycle. It can take anything from 10 days to three weeks to fully complete the cycle.
You know your tank is cycled when your added ammonia has fully been converted to nitrate in 24 hours. Test your tank each morning, before you add ammonia. If you constantly see a zero ammonia reading, and a high nitrate reading, then your tank is cycled. You can keep feeding the colony with ammonia until you are ready to add your fish.
Ready to add fish ? Then do a big waterchange with de chlorinated water (around 80% change) to remove the excess nitrate, but don't add any ammonia, then add your fish all at once. No need to feed sparingly for the first month. Your tank is fully cycled, and will deal with all the waste that the fish produce.
It's a fairly simple procedure, and I've deliberately kept this explanation basic. If you're looking for all the scientific names of the bacteria involved, then a quick google will give you all the information you need.
