USING HOUSEHOLD AMMONIA FOR HUMANE CYCLING OF A TANK 

The conventional method of using a hardy fish to cycle a new tank has some disadvantages. First, subjecting a fish, however hardy, to ammonia and nitrite stress may be unnecessarily cruel. Second, you have to have some use for the fish after the tank is cycled. Third, this hardy fish may bring in pathogens to your aquarium environment. 

Originally published as:

Koga, James S. Use Household Ammonia to Humanely Cycle a Tank¹. Freshwater and Marine Aquarium, 19, no. 4 (December 1996): 213-214. 

Some time ago, I came across a post in the Aquarium groups on the Internet that mentioned adding Ammonium Chloride to cycle a saltwater tank, and I believe the process is (or was) described in the marine FAQ files. Later on, I came across an article on Goldfish culture (Meyer). It recommended the use of household ammonia to cycle the tank. Instead of using a fish to produce ammonia, why not add ammonia itself?. 
 

I use clear, unscented, no additives, 100% pure household ammonia from the supermarket. A quart costs less than a dollar and might last you for years. You will want to place it in a container that allows dispensing by drops. An old water conditioner bottle with the right type of top is good: BE SURE TO LABEL IT! Keep it out of the reach of children. Alternatively, some aquarium stores have started to sell bottles of Ammonium Chloride for this purpose. 

A starter culture of Bacteria can be added by two methods. Some material from an established aquarium can provide the needed innoculum: some water, a piece of used filter material, a decorative object, a handful of gravel. This shares the disadvantage of the donor media method of bringing in pathogens. However, if the donor tank has been in good health, there may be no compelling reason to avoid donor material. The second method is to use one of the commercial preparations of nitrifying bacteria. I have had good results with Hagen's Cycle (TM), but I note that there are many other products available, with more coming on the market all the time. 
 

1. Set up the Aquarium: filters, heaters, lights and all. Be sure to dechlorinate/dechoraminate the water. 

2. Place the "Ammonia Alert" in the aquarium. It usually needs a day or two to acclimate to the aquarium. 

3. Keep the filter running throughout this process. 

4. Provide extra aeration if possible. With an outside hang on-the-back power filter, a good way to do this is keep the water level a couple of inches lower than usual so that water falling from the filter makes a bigger splash than usual; the more bubbles breaking on the surface of the water, the more oxygen is in the water, and the bacteria need oxygen to grow. You can raise the water level when you are ready to add fish. Other types of filters may offer other aeration increasing options. Or, the addition of a simple airstone might suffice. 

5. If you can, try to keep the temperature of the water up in the low to high eighties (F) for reasons explained above. Remember to adjust the temperature back down to a livable temperature for your fish before adding them. 

6. Inoculate your aquarium with bacteria, either by placing some material from an established aquarium or use a commercial bacteria culture. I put a packet or two of Cycle"(TM) in the water. Wait about an hour. 

7. Put 3-5 drops of pure ammonia in the tank, or enough ammonia to turn the "Ammonia Alert" dark. If it doesn't darken, add more. Wait for the ammonia alert to go back to a "safe" level. This may take several days. Repeat this many times, each time waiting for the ammonia level to get back to "safe" before adding more ammonia... 
 

9. While the ammonia level is at "safe", test for nitrites. If it shows zero nitrites, proceed to the next step. If it does not, go back to step 8 and repeat step 8 three to four more times and then test again for nitrites. 

10. Adjust the heater down to a livable temperature for the fish. Do a very large water change (about 90%), and then  you are ready to add fish: you can go to the fish store now. (Remember, only add dechlorinated water of about  the same temperature to the tank in order not to stress the bacteria with too drastic a change.) 

Johnson, Erik L. July 1993. Turn Up the Heat! Tropical Fish Hobbyist XLI (11): 80-81. 

Lawson, Thomas B. Fundamentals of Aquacultural Engineering. New York, NY: Chapman and Hall, 1995. 

Meyer, Stephen M. November 1993. Goldfish From the Beginning, Part II. Aquarium Fish Magazine, 6(2):32-42. 

In the time since this article was originally published, I've realized that there are some things missing from this article that would have made it a lot more useful. Also, some other experiences with the method have been reported. So here we go:

1. The label on my bottle of ammonia says it contains: "pure ammonia"; despite this, household ammonia in the U.S. is mostly water.  It is a solution of ammonium hydroxide (also called "aqueous ammonia"). The strength can vary between 5 to 10 % ammonia (that's 50,000  to 100, 000 ppm). Meyer's latest publication about this method (see below) states that since the concentration of household ammonia can vary, it's best to experiment until you bring the initial level of ammonia in the tank to 1-2 ppM. He suggests starting out with a 0.25 teaspoons (which would be about 1.25 mL) for a 20 gallon tank.
 

The Ammonia Alert, when used as directed,  does not allow you to accurately raise the ammonia level past 0.5 ppm. However, you can calibrate your Ammonia Alert by counting the number of drops of ammonia it takes to turn it to the "toxic" level.  (Unfortunately, the Ammonia Alert does not respond instantly, so this may be a somewhat tedious process.) Multiply the number of drops by two to get the number of drops it would take to achieve a 1.0 ppm level and multiply times four to get the number of drops it takes to achieve a 2.0 ppm level. Keep in mind that due to the different net volumes in different tanks, this number of drops might be different for each tank you own.

3. Russell Taylor and Greg Tong experimented with the method and found that with tank water with low alkalinity², the addition of even these small amounts of household ammonia caused pH spikes that retarded the growth of the bacteria. Since my own water is hard, alkaline, and of a high alkalinity, I did not have the problem. There are some websites that state that the pH of household ammonia is in the neighborhood of 11 to 12, which is quite alkaline. Hopefully, a good buffering product (say, Seachem's Neutral Regulator, which is quite inexpensive³) would take care of the problem.  Some partial water changes after cycling would be gentle enough transition to get the tank back to the desired unbuffered state.
 

Also, the revelation that we are probably not dealing with Nitrobacter or Nitrosomonas throws some doubt on the efficacy of commercial bacterial starter cultures (Hagen Cycle, Fritz-zyme, etc.). However, it is possible that the companies involved are constantly reformulating their products or that their products are effective, whatever bacteria they happen to be using. Keep in mind that if you do choose to use one of these products, you are probably not doing much  harm to the process: in view of the fish that you will not lose due to your cycling efforts, the cost of the products is minimal.

Conclusions:

The method remains viable.  I don't see any reason for people to NOT use the method if they take the proper precautions. After looking at the newer material,  I don't see any reason to change the basic procedure, either. What should be added is a warning to buffer your water if you have low buffering capacity (you probably should be doing this anyway, then?) and to aim for a target level of 1-2 ppM ammonia while cycling.
 

In case you are not familiar with the nitrogen cycle, here is an excellent explanation:

• Beginner FAQ: The Nitrogen Cycle

• Russell Taylor's Cycling a Filter without Fish
• Chow, Chris. Fishless Cycling Revisted
• Algone.com's Fishless Cycling of The Aquarium
• How To Establish the Nitrogen Cycle without Fish (Aqualink Column)
• Greg Bunch's Cycling with Household Ammonia: A Success Story.
• Cycling Safely: The Fishless Method
• SUIC Fisheris Bulletin 9A: Basic Principles of Biofiltration and System Design (This describes some calculations about how much ammonia to add in a fisheries situation).
• Curt Lemricks' Fishless Cycling gives a rationale for using Ammonium Chloride vs household ammonia.
• Seachem's product page for the Ammonia Alert.

• Koivet's Seeding a Biofilter and No More Cycle: How?

Some supplementary pages about Household Ammonia:

• Environmental & Scientific Terms Revisited gives the pH for Household Ammonia as 12.
• Fuming with Ammonia - Page 2 Handle with care says that household ammonia is less then 5 percent.
• Missiippi State Extension Service Household Cleaning Products states that household ammonia is 5 to 10 percent. 
• MMWR Epidemiologic Notes and Reports Ammonia Contamination in a Milk Processing Plant states that household ammonia is 5 to 10 percent. 
• Kings County, Washington, Hazardous Waste Management Program Waste Directory - Ammonia Solution states that household ammonia is 5 to 10 percent 

Meyer, Stephen M. February 1999. Cycling Fishless [Ponds and Pondfish Column] . Aquarium Fish Magazine, 11 (2):81.

Hovanec, Timothy A.  March 1997. Nitrifying Bacteria [part 1] Aquarium Fish Magazine, 8 (3):44-52.

Hovanec, Timothy A.  April 1997. Nitrifying Bacteria [part 2] Aquarium Fish Magazine, 8 (4):32-43.

Hovanec, Timothy A. and Edward F. DeLong. August 1996. Comparative Analysis of Nitrifying Bacteria Associated with Freshwater and Marine Aquaria.  Applied and Environmental Microbiology 62(8):2888-2896.

Footnotes:

¹  Or: How to use Household Ammonia to Split an Infinitive.

²  The water chemistry definition of "alkalinity" is not, as one might assume, how basic the solution is, but how much it resists changes in pH, which is the same as its "buffering capacity".

³ And, by the way, I failed to mention in the article that I habitually use this product in my tanks, though I don't think it made any difference in terms of pH spikes, given my water conditions.