My Fishless Aquarium Cycle


I've done a lot of reading on fishless cycling. The majority of the articles have been formula only; add this, do that, etc. Many are extremely scientific while others are more matter of fact. I tried to combine all of these readings into a guide that I could work with. This offering is basically a diary of my recent, and first, fishless cycling experience along with some of the knowledge that I've gained in the process.

The tank in question is a 20-gallon long. A Penguin Bio-Wheel Mini, minus bio-wheel, and a used pre-filtered Renaissance Prime 10 canister filtered the tank. The canister was filled with Bio~Max and had two Fluval 203 round sponges in the bottom of the media container. The tank was heated with a Tronic 100W and was sans light strip. Gravel was taken from an established tank and the filter pad for the Penguin had been sitting in an Emperor 400 on the same established tank for over a month. Some larger rocks and pothos from this tank were added also.

The Aquarium Pharmaceuticals Master Test Kit, 2-bottle Nitrate (NO3) Test Kit, and the 2-bottle salicylate based Ammonia (NH3/NH4) Test Kit were used. The Nessler-based ammonia test found in the Master Test Kit gave what appeared to be faulty readings so the salicylate based test was used exclusively. The NO2 test reads total nitrite and the NO3 test kit reads total nitrate or nitrate as nitrate ion. All of these kits read parts per million (ppm) which is equivalent to milligrams per Liter (mg/L).

I found what was labeled as "Clear Ammonia" at Wal-Mart. The 64-fl.oz. bottle cost less than a dollar and the ingredients read: softened water, ammonia, chelating agent, contains no phosphorus. It was assumed that this was probably a 10-20% solution and the chelating agent keeps the ammonia and the water combined so we don't have to shake it up to mix the two before each use. I measured the ammonia using a 1/4-teaspoon measuring spoon. To establish how much ammonia I would need to achieve a 5ppm concentration I added a 1/4-teaspoon then tested the water. This indicated approximately 1-2ppm so I added another three 1/4-teaspoons, retested the water and the desired 5ppm, give or take, was established.

My plan of attack was to maintain the temperature at 88 degreesF, in an effort to increase the growth rate of the bacteria. I also wanted to maintain a 5ppm level of ammonia throughout the entire cycle process. That is, I wanted to maintain 5ppm of ammonia until it was completely consumed in a 24-hour period resulting in an ammonia level of 0ppm and a nitrite level of 0ppm. To achieve this I initially added enough ammonia to reach 5ppm then approximately every 24-hours I would test the ammonia level and add just enough to bring the level back to 5ppm.

I was a little concerned about maintaining the ammonia at 5ppm throughout the process because of the possibility of a pH crash. Others had reported this in the research materials. Consulting the Tom's Place message boards suggested that this problem was closely related to the carbonate hardness (KH) of the water, i.e. the pH buffer. A low KH could be eaten away at by the acids created during the nitrification process resulting in a drop in pH. A possible solution to this is monitoring the KH and pH levels and performing water changes to replenish the buffer. My KH reads 11 degrees and a drop of 2 degrees was noticed during the last few days of the cycle. The pH remained at 7.6 for the entire cycle.

I kept a record of my readings in a spreadsheet; the data follows. Where there is no number, that test was not preformed. The ammonia and nitrite tests were preformed every time while the nitrate test was preformed only occasionally but more often towards the end. I had to enter zeros for the nitrates even when I didn't perform a test so my chart would come out correctly. All readings are after a, approximate, 24-hour period. If the ammonia level was found to be below 5ppm, then ammonia was added to reach 5ppm.

Date & Time Ammonia Nitrite Nitrate pH KH GH Temp
7/31/11 23:33 3.00 0.00 0.00 7.6 76.0
8/1/11 11:54 2.00 0.00 0.00 80.0
8/2/11 1:33 2.00 0.00 0.00 84.0
8/3/11 0:30 1.00 0.00 0.00 84.0
8/4/11 1:43 0.50 0.00 0.00 84.0
8/4/11 23:01 2.00 0.25 0.00 88.0
8/6/11 2:17 0.50 0.50 0.00 7.6 11.0 88.0
8/6/11 21:27 0.50 0.75 0.00 88.0
8/7/11 16:57 2.00 2.00 20.00 7.6 88.0
8/9/11 18:06 0.00 2.00 30.00 7.6 11.0 88.0
8/10/11 22:09 0.00 2.00 30.00 88.0
8/12/11 0:41 0.00 1.00 30.00 88.0
8/13/11 0:22 0.00 0.50 40.00 7.6 9.0 88.0
8/15/11 23:22 0.00 0.00 40.00 7.6 88.0

You'll see that during the first few days I broke from my plan and maintained a lower ammonia level. Beginning on 8/4 I started maintaining the 5ppm ammonia level planned. I was also wishy-washy on the temperature. The whole cycle lasted about 16 days.

When 5ppm of ammonia was consumed in a 24-hour period, resulting in nitrites reading 0ppm, I did a 100% water change and added my fish. Currently the tank holds; 7 long-finned leopard danios, 4 bronze coryadorus and 3 ottos. Future guest, currently quarantined, will include 3 three-lined coryadorus and some ghost shrimp. Also due to some technical difficulties, with the canister filter leaking, an Emperor 280 now filters the tank with the bio-max lying in the filter.

I hope that this will be helpful for those of you undertaking your first fishless cycle. The key thing to remember here is patience, patience, and lastly patience.

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