** Become a ThinkFish Super Subscriber **

It takes time and money to keep ThinkFish going, if you'd like to help, then a Subscription of your choice would be fantastic. Your subscription will help fund new articles, help pay for server costs and help fund development and promotion initiatives, helping us bring you more of the good stuff you love! You'll also see less ads. Why not become a Super Subscriber today!?


Author Topic: FISHLESS CYCLING (OLD METHOD) - HOW TO DO IT  (Read 5323 times)

0 Members and 1 Guest are viewing this topic.

Offline Sue

  • Global Moderator
  • Hero Think Fishy Member
  • *****
  • Posts: 8862
  • Likes: 309
« on: September 19, 2012, 03:16:31 PM »
  • Likes On This Users Post 0
Fish produce ammonia, by breathing it out, and their waste decomposes to make it. Ammonia is toxic to fish – it burns their skin and gills making it difficult for them to breathe. A type of bacteria grows in the filter which turns the ammonia into nitrite (with an ‘i’). Nitrite is also toxic – is stops the fish’s blood absorbing oxygen properly, and causes nerve damage. A second type of bacteria grows in the filter which turns nitrite into nitrate (with an ‘a’). This is only toxic at high levels, and it is removed by regular water changes.
These bacteria take several weeks to grow in enough numbers to cope with the ammonia made by the fish. The process of growing the bacteria is called cycling.

There are two ways to cycle a tank – with fish and without. Both take several weeks to complete, typically between six and eight weeks. Cycles have been known to be completed in less than four weeks, but this is rare. It has also been known to take longer than eight weeks. It is difficult to give an exact time as there are so many variables.
Several things can affect how fast the bacteria grow – the pH of the water, the hardness of the water, the temperature of the water etc. The source of the bacteria is your water supply, but your water company adds chlorine or chloramine to kill bacteria. The amount of bacteria that manage to escape being killed will also affect the length of time it takes to complete the cycle.

If fish are put into a tank that has no bacteria in the filter, they will suffer from the effects of ammonia and nitrite poisoning. It requires a lot of hard work on the part of the fishkeeper to keep the fish alive for up to two months while the bacteria grow. This process is called a fish-in cycle.

Alternatively, a fishless cycle can be carried out before fish are put in the tank. This involves adding a source of ammonia to the tank to simulate fish waste, and this encourages the bacteria to grow, so the colonies are already present when fish are added. A fishless cycle can be done by adding fish food or ammonia solution to the tank.
Fish food has the problem that it is harder to control the amount of ammonia that is actually going into the tank, as the food has to decompose first, but people who cannot find the correct type of ammonia solution have no choice but to use it. In this case, add fish food every day, removing old food before it starts to grow mouldy, and follow the testing instructions for the ammonia solution method. When the cycle is complete, only add a few fish at first as you won’t know just how many bacteria have grown in the filter. Add more fish a few at a time as for fish-in cycling.

Fishless cycling using ammonia solution

There are several things required for a fishless cycle.

Pure ammonia solution


The ammonia solution must be pure. If there is a list of ingredients, it must have ammonia or ammonium hydroxide, water, and nothing else. If there is perfume, soap, detergent or surfactant listed, don’t buy it. If there are no ingredients listed, and the bottle is see-through, shake it. If the bubbles are large and burst quickly like water, it’s fine. If it foams and the bubbles last a long time, don’t buy it.  If in doubt, google the manufacturer’s website.
In the UK, the places that usually sell ammonia are Homebase, in the household cleaning section; eBay; Amazon. Small local diy shops may also sell it. If you find the Jeyes Kleen Off brand, be aware that there are other products in the Kleen Off range; the bottle must have the word ammonia on it.

Testing kit
You will need to be able to test for ammonia, nitrite and pH. A lot of strip testers do not contain ammonia tests. Liquid reagent test kits can be purchased as a master test kit containing everything needed, and they work out cheaper per test. There are several makes on the market. Some testers use ppm as the measure, some use mg/l. These units are so close we can regard them as being the same thing.

If you use a liquid reagent kit, make sure you wash the test tubes thoroughly and dry them with a paper towel/tissue after each use. There have been reports of people getting false readings caused by chemicals left in the tube from last time!

If you have bought the API liquid testers, there are two quirks to be aware of.
Firstly, the ammonia test can show inaccurate results when read under fluorescent tubes and energy saving bulbs. Whenever practical, the ammonia test should be read in daylight and when this is not possible, under an incandescent light bulb or halogen light bulb.
Secondly, the nitrite test can behave oddly if the reading is off the top of the scale. If the liquid in the bottom of the tube turns purple immediately on adding the drops, it is probably too high for the tester to cope with. It may also go an odd shade of greeny blue after mixing and standing. The way to check this is to dilute a sample of tank water with tap water, say 1 fifth tank water and 4 fifths tap water, and measure it again. If the reading is now somewhere on the scale you’ll know your tank water is off the scale.

Measuring dropper
This is for accurately measuring the ammonia solution. A medicine dropper with different amounts marked, or a syringe is ideal. They can be purchased from pharmacies or even eBay. Tip – if buying a syringe from a pharmacy, ask for baby medicine dosing syringes or you’ll get the third degree about why you want one if you just ask for a syringe.

The first thing to do is set up your tank and let it run for a day or so. This gives time to make sure the equipment is working properly, and for any dust from the gravel or sand on the bottom to clear.

While the tank is settling, use your test kit to test your tap water. There may be slight amounts of ammonia and nitrite in the tap water, and probably some nitrate. The UK allows drinking water to contain 0.5 ppm ammonia, 0.1ppm nitrite and 50ppm nitrate.
With pH, measure a sample of freshly drawn tap water, and allow a glass of water to stand for 24 hours, then test it again. You will probably find a difference between the two. It is useful to know how much the pH of your water changes on standing - the water in your tank has also stood for a while!
It is also useful, though not vital, to know the KH of your water. A test kit can be bought for this, or the information might be available on your water supplier’s website. If they give it, it will be given in the same section as hardness and may be called alkalinity.

You will also need to work out for yourself the best times of day to spend a few minutes with your tank. You will need to test the tank water twice a day at 12 hour intervals. For people who work “9 to 5” jobs, this is usually in the morning before going to work, and the same time in the evening. Those with more unusual working hours will have to use different times!

You will find this method is slightly different from the methods you will find on other sites. With the original fishless cycling method, the tank was dosed with a higher level of ammonia from the start. In recent years it has been found that high levels of nitrite (and nitrate) can actually inhibit the growth of the nitrite eating bacteria. This method starts with a low dose of ammonia, increasing the dose only once the nitrite eaters are growing well.


Fishless cycling is better done without plants in the tank as they require the tank lights to be on. They can be put in just before the fish once the cycle has finished.
Turn the tank lights off. You will have a lot of ammonia in your water over the next few weeks, and ammonia + light = algae. You may well get algae growing even with the light turned off, but not nearly as much as with the light on.
Turn the heater up to give a temperature around 30 deg C (that’s the mid 80’s F). These bacteria grow faster at higher temperatures.

This method of fishless cycling is called the “add and wait” method. It involves adding ammonia solution, waiting till the level drops low, then adding more ammonia, waiting till it drops, adding more, waiting till it drops…….and so on.

1. Add enough ammonia to give a reading of 1ppm or mg/l (whichever your test kit uses). If you have bought 9.5% ammonia you will need to add 0.1ml for every 10 litres of tank water. Check the ammonia reading of the tank about half an hour after adding it (to allow it to mix thoroughly). If the reading is over 5ppm, it is advisable to replace some of the water as the wrong species of bacteria can grow if the ammonia level is too high. If the bottle of ammonia does not give the strength, add .05ml per 10 litres, adding more if the reading is too low after half an hour.

2. Check the ammonia reading at 24 hour intervals. You won’t see a change for several days, maybe even a couple of weeks. Eventually the reading will start to fall. Start testing for nitrite as well. Now that you have increasing levels of nitrite, test pH daily as well as ammonia and nitrite. This will enable you to catch a possible pH drop quickly.

3. When the ammonia reading drops to zero, add enough ammonia to get the reading back up to 1ppm. Top up the ammonia every time the reading drops to zero – but only once in any 24 hour period. If the reading falls within 12 hours, wait till 24 hours after adding the last dose.

4. The nitrite reading will probably go off the scale. Keep adding ammonia daily until nitrite too drops to zero within 24 hours of adding ammonia. On average, it takes twice as long for nitrite to fall as it does for ammonia. If you can find the time, it is useful to do a water change whenever the nitrite reading reaches the top of the scale; however it is not vital that water changes are done, only if you wish to do them.

5. Once the nitrite reading drops to zero, increase the amount of ammonia added to give a reading of 2ppm half an hour after adding it. Continue testing for both ammonia and nitrite after 24 hours. When both read zero again, increase the ammonia dose to give 3ppm after half an hour. Repeat again to 4ppm ammonia doses.

6. Once you are adding 4ppm ammonia and are getting zero readings for both ammonia and nitrite after 24 hours, start testing 12 hours after adding a dose of ammonia. Continue dosing ammonia once every 24 hours.

7. When you have zero for both ammonia and nitrite within 12 hours, you are almost there. But keep adding ammonia daily for a week. Some people find they get a bit of a wobble and ammonia and/or nitrite starts to show up again for a few days. Waiting for a week of double zeros before getting fish means there is no danger of this happening with fish in the tank. If you can’t get to the shop at the end of this checking week, just carry on adding ammonia daily till you are ready to go fish shopping.

8. The nitrate level will now be very high. Just before you buy your fish, you will need to do a very large water change to remove all this nitrate, somewhere in the region of 90% of the water. Once it is back up to temperature, you can get your fish. Turn the heater back down to the temperature needed by the fish you are about to buy.

Because you have grown enough bacteria to cope with 4ppm ammonia you can add a lot of fish at once, unlike cycling with fish. It is safe to add about three quarters of your stocking list, though bear in mind that for the first six months you should keep to a maximum of one inch adult size of fish per gallon of water to allow the tank to mature.

You may well have brown algae over everything by now. Don’t worry, it will go away!

Water changes
Unlike cycling with fish, you will need to do few water changes.

If you accidentally overdose the ammonia, do a water change to get it down. At levels of above 8ppm, the wrong type of bacteria grows.

If your nitrite reading goes of the top of the scale, it will inhibit the growth of the bacteria. A water change will drop the reading to somewhere on the scale.

If your tap water pH is below 7.0, or if your KH is 5 or below, you are in danger of a pH crash. You will need to keep an eye on the pH level during cycling. If the pH drops below 6.5, a water change is needed to raise it again. At these low pH levels, the bacteria become dormant; they don’t die, they just stop multiplying and the cycle stalls. There are ways of preventing pH crashes. If you find this happening repeatedly, ask for advice on what to do.

Ways to speed up a fishless cycle

If you can put some already mature filter media into your filter this would seed the filter, reducing the cycling time. The media could be from another tank you have, a friend’s tank, or very occasionally a shop. (Very few shops will offer this!). If you use media from someone else’s tank, make sure it is disease free.

There are products on the market that claim to instantly cycle your tank. You need to be aware that a lot of them don’t work. Some grow the ammonia eating bacteria quickly but not the nitrite eating bacteria. Try one if you wish, but be sure to use them to kick start the cycling process, not replace it. It’s possible you may actually find one that speeds things up!

Offline Sue

  • Global Moderator
  • Hero Think Fishy Member
  • *****
  • Posts: 8862
  • Likes: 309
« Reply #1 on: April 28, 2013, 03:19:54 PM »
  • Likes On This Users Post 0
I have just cycled a small tank for a betta (siamese fighting fish). Because the tank would have only one fish, it would be understocked so I cycled only to 2ppm ammonia rather than the 4ppm in the method above. As a guideline, here is a summary of the cycle. It is important to remember that every cycle is different. Yours may be longer or shorter than mine. And you may not suffer a pH crash as I did. For people with soft water, my cycle proves the importance of checking the pH on a regular basis!

There is a rather long thread giving more detail (and a lot of chit chat as well) here

It was easier for me to dose ammonia in a morning around 8.30am. 24 hour tests were done at 8.30 am and 12 hour tests at 8.30pm.

25 litres
No substrate or decor
Temperature 30oC

Tapwater parameters
Ammonia 0
Nitrite 0
Nitrate 5
pH (after standing 24 hours) 7.4
GH 7
KH 3

Day 1
The tank was set up and ammonia added to give a reading of 1ppm.

Days 1 - 12
The ammonia reading remained constant at 1ppm

Days 13 - 14
On day 13 the ammonia reading had halved, and on day 14 it was zero. Ammonia was added to give a reading of between 0.5 and 1ppm.

Days 15 - 29
Ammonia dropped to zero in 24 hours every day, nitrite rose by around 2.5 every day. 100% water changes were done every time the nitrite reading reached 5ppm. Ammonia was dosed every day to between 0.5 and 1ppm.

Days 30 – 33
Nitrite had slowed down considerably, the readings 24 hour hours after adding ammonia showing no higher than 0.5. No water changes were done during this time, ammonia was dosed daily to give a reading of between 0.5 and 1ppm

Day 34 and 35
Both ammonia and nitrite were zero 24 hours after adding ammonia. The ammonia dose was increased on day 35 to give 2ppm

Day 36
Nitrite was between 2 and 5, obviously the jump in ammonia dose was too great. 100% water change done and ammonia dosed to give 1ppm

Day 37 -39
Double zeros after 24 hours on both days so the ammonia dose was increased slightly to 2ppm on day 39. Started testing 12 hours after adding ammonia – both tests showed small amounts present after 12 hours, but zeros at 24 hours.

Day 40
pH crash.
The 24 hour tests showed the pH to be less than 6.0. A 100% water change was done and enough bicarbonate of soda added to raise the KH to 13o German hardness, together with a 2ppm dose of ammonia. The 12 hour reading showed that there was only a trace of ammonia left but that nitrite was off the top of the scale ie over 5ppm. From now on, pH was checked at every 12 hour and 24 hour testings.

Day 41
The 24 hour tests showed zero ammonia and only a trace of nitrite. The sudden drop in pH followed by a very rapid increase in both pH and KH probably shocked the nitrite eaters so that it took well over 12 hours for them to remove any nitrite. The ammonia eaters appear to have been unaffected.

Day 41 - 44
Ammonia was dosed daily to give 1ppm. During this time the water was not tested for 48 hours due to being away (though someone did add ammonia for me). On return the ammonia test gave a zero result and nitrite was present in only a trace 12 hours after ammonia dosing.

Day 45 – 47
The ammonia dose was increased to 2ppm. This was cleared to zero ammonia and nitrite in 24 hours; in 12 hours ammonia was zero but there was a trace of nitrite. A 95% water change was done on day 47 to remove the high level of nitrate, bicarbonate of soda was not added.

Day 48
Following zeros at 24 hours, a betta was purchased  ;D

** Become a ThinkFish Super Subscriber **

It takes time and money to keep ThinkFish going, if you'd like to help, then a Subscription of your choice would be fantastic. Your subscription will help fund new articles, help pay for server costs and help fund development and promotion initiatives, helping us bring you more of the good stuff you love! You'll also see less ads. Why not become a Super Subscriber today!?

Assess Tankmates In The Tropical Fish Community Creator

Topics that relate to "FISHLESS CYCLING (OLD METHOD) - HOW TO DO IT"

  Subject - Started by Replies Last post
0 Replies
Last post August 15, 2013, 10:19:33 AM
by Sue
19 Replies
Last post July 01, 2016, 04:08:54 PM
by Sue
10 Replies
Last post January 16, 2017, 09:06:03 PM
by Paddyc
425 Replies
Last post May 19, 2017, 10:08:56 PM
by Matt
83 Replies
Last post March 14, 2018, 11:47:07 AM
by Sue
21 Replies
Last post December 04, 2018, 07:55:47 PM
by fcmf
14 Replies
Last post December 03, 2018, 08:04:25 PM
by Joolia

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 

Think Fish © 2004-2018 | Keeping Tropical Fish Forum - Everything you need for your Tropical Fish hobby
Tropical Fish Market Place
Legal | Contact Follow Think Fish on: