Fishless Cycling by Fishguy2727
It is now understood that fishless cycling is the ideal way to cycle a tank unless you can use mature media from an established tank. However, there seems to be some debate over exactly what is the best method of fishless cycling.
One important thing to remember is that cycling with fish has worked 'well enough' for most of us before we ever used fishless cycling. If done properly it can be stress free for the fish and result in a healthy setup when done properly and patience is applied.
To fishless cycle just get the tank going with all the equipment running and use a source of ammonia to get the nitrifying bacteria established. This is where the main debate kicks in.
What is the best source of ammonia is what is debated over and over. Many will say to just stick in some fish food or dead shrimp (frozen shrimp from the seafood section is the usual method). Some even recommend the exoskeleton from eaten shrimp to be used. There is one major issue with all of these, a delayed start and an unpredictable, uneven release of ammonia. This also requires the establishment of Bacillus spp. of heterotrophic bacteria to breakdown these sources of ammonia into ammonia, since these do not simply give off ammonia by themselves or automatically. This bacteria is what is responsible for the cloudiness typical of 'new tank syndrome'. Since there will not be a constant release of ammonia and since by the time nitrites are back down to 0 (what is considered 'cycled') there will no longer be any ammonia being released these are not good sources of ammonia.
The ideal source of ammonia is ammonia. Bottled ammonia for housecleaning purposes, without dyes or artifical scents, is the ideal source.
In addition, to speed the cycle, raise the heater to the highest it will go. Since the nitrifying bacteria thrive in 95-100F it will accelerate the cycle if the temperature is higher.
On the first day you need to have your ammonia test kit, bottle of ammonia, and a dropper. Slowly add ammonia one drop at a time until you reach the high end of the scale on the test kit. You will need to test many times. Add a drop, give it a minute to be distributed in the tank, take your sample, and test. You must count how many drops you add to get to this high concentration. You may be able to add a few drops if you can tell it is not bringing up the concentration very fast. For example, if you added 5 drops, the concentration is 1.0, and the scale goes up to 8.0, you can add another 5 drops, not just one, and then test again. Once you establish how many drops it took to get to the high end of the scale, write it down. This will be how many drops you add EVERY SINGLE DAY until you are cycled.
You can test ammonia and nitrite daily to monitor the progress. This method will result in very high, off the chart, ammonia readings at first. This is fine since there are no fish to be stressed by it. The ammonia concentration will rise and then begin to fall. As it falls the nitrite concentration will rise. It will rise and then fall. Once nitrite is back down to 0 you are cycled and can now add fish.
DO NOT STOP ADDING AMMONIA until fish are in the tank. If you stop adding ammonia because you are cycled, and then wait a few days before adding fish, most if not all of the nitrifying bacteria will have died because there was no food for them. Add ammonia until you add fish. Do not add ammonia the day you add fish to ensure there is none in the water when the fish go in.
With this method, theoretically, you could fully stock a tank in one day once the tank is cycled for a very high bioload. This is not recommended though because it is easy to throw off the balance of nitrifying bacteria and the bioload (fish plus food). However, because of this, this method is especially helpful when setting up tanks where all the fish should go in at about the same time, such as many mbuna setups.
One response to bottled ammonia being the best source of ammonia is that the other sources (food, shrimp, etc.) have worked when the fishkeeper has used them. This brings us back to the fact that cycling with fish has worked 'well enough' for us for so long. Since most people add fish slowly, as is recommended, when they have fishless cycled it is very hard to tell that the method actually worked as well as they think and that it was not simply that they thought they had fishless cycled when really they ended up cycling with fish. As stated, when done properly cycling with fish can work (but it is much less likely to than fishless cycling and very easy to cause massive amounts of stress and even death to the fish). So if they added fish slowly enough after they had 'fishless cycled' they may not ever register any ammonia. All they did was delay the time they put fish in.
One thing that I have seen repeatedly is that halfway through the fishless cycle the amount of ammonia being added should be reduced or even cut in half. I have not found any information explaining or supporting this, so I do not recommend it. It does not make sense to me at this time and I see no issue with using the full dose throughout the entire cycling process. It is stated on many websites, but they do not explain why this is needed. As far as I can tell it is simply something that has been read and re-stated repeatedly. If anyone does have any idea as to why, please let me know.
Remember to turn the temperature back down to the desired setting before adding fish.