Fishless Cycle Question!

[interpet123]

Hi all, i was wondering if anyone could give me a rough idea of how many weeks it would take to cycle a 150 litre tank? Any replies would be much appreciated. Alex

 

[Owen386]

The Fish-less Cycle Regardless of size of tank seems to take around 4-8 weeks. But that's Just My opinion of reading personally have only experienced one which lasted about 4 weeks. Good Luck!

-Owen

 

[interpet123]

Thanks, i will need it! I am totally new to cycling a tank, and am XTREMELY nervous, but very curious! Thanks again

 

[waterdrop]

Agree. The actual elapsed time of each individual fishless cycle varies wildly and over the years we've described it in different ways. For a long time I remember us describing the average as 3 to 6 or 8 weeks. I often no longer mention the 3 week thing as I've seen too many fishless cycles where the beginner thought it was finished in 3 weeks, only to have the filter give nasty spikes after fish were added. So when a fishless cycle seems to end in 3 weeks I like to encourage the beginner to just keep adding ammonia for a second qualifying week and push the whole thing out to a month. I don't know exactly why that seems to make it more robust but it just does, at least based one what we've seen here I think.

At the other end of the scale we often see some of the more stubborn fishless cycles finally draw to a close at about 70 days (making it a bit longer than 2 months, obviously) and we've certainly seen a number of cases going way up over 100 days. Since cases come in from all over the world and there can be a huge variety of bacterial and water conditions that feed into people's homes around the world, this doesn't seem surprising to me. Actually, what always seemed surprising to me was the ubiquity of presence of our two needed autotrophic bacterial species around the world. They are just more or less universally present in whereever there is fresh water. Give it enough time and even if there were only one or two cells present, they eventually grow and divide in almost any filter!

Another thing for the beginner to remember is some of the threads you read are written by people who are using some form of "mature media" (filter media that have spent months or years in another tank) put in to their new filter. This makes a huge difference in how quickly the needed sizes of bacterial colonies grow up. These "mature media" fishless cycles can be done in only 1, 2 or 3 weeks. So one must not use them in forming a mental average of how long the "standard" fishless cycles (with no mature media) will likely take.

By far the biggest factor (we think) in how long a fishless cycle takes is the total unknown of how many of the correct live bacteria were in the original tap water. That starting number is always an unknown and by definition makes a huge difference. Water chemistry and organic things in the water then could explain other differences in time and also eventually the skill with which the fishless cycler observes and runs the cycle. The quality of the filter may play a small role, but generally these bacteria will populate cheap filters about as well as expensive filters.

~~waterdrop~~

 

[interpet123]

This is all great stuff, but as i am new to tropical tanks, i have NO IDEA about what i'm doing! I am not bothered by the amount of time it takes, i am a generally patient person. It's just that i have read so many different articles, pages and guides to fishless cycling that my mind is about to explode!! But all i want is what's best for my future fish, which i understand will take time and effort which i am willing to give. I just cant get my head around how complicated it is. Like the levels of ammonia, nitrate, nitrite, PH.....

 

[OldMan47]

If you merely dose some ammonia to around 4 ppm and wait for it to process, it will eventually produce a population of ammonia processing bacteria. Once that first dose of ammonia is gone, you dose up again to give those ammonia processing bacteria something to live on while you wait on the nitrite processors to start doing their job. Once both kinds are present you start testing every 12 hours and dosing as needed every 24 hours, only needed if the ammonia has gone back to zero. The final phase is a case of finessing those bacteria populations to move all of the ammonia and nitrite in 12 hours. Once that happens, you do your huge water change to drive nitrates way down and you are ready for fish instead of a new ammonia dose.

I hope this simple picture is easier to understand than the details we usually use here. Both ways of looking at it give the same process and results but sometimes it is easier to just look at each bacteria separately as if the other did not exist. I feel like we too often give too many details and it just confuses new people.

 

[interpet123]

Thanks SO much, that helped ALOT, so.... what is the correct level of ammonia?? And when thats colonised, do you lower the dosage to give them something to live on?? Because if you carry on with he same amount of ammonia being added, surely the levels would keep rising???(i have no idea i'm asking you )

 

[BIG BAD BARRY]

Have a read of the Beginners Resource Center in Your New Freshwater Tank.
Also, have a look at some cycling posts.
Have a seach for a topic by Gvilleguy who has produced a good step by step guide.

This is my brief explanation:
You should initially dose 4-5ppm ammonia and test daily (24hrs). Wait for it to drop to 0ppm and then re-dose back up.

When the nitrites go above 5ppm, what we term as a spike, then drop ammonia dosing to 2-3ppm. Again, only re-dose once it has dropped to 0ppm. You are still testing daily (24hrs).

Once nitrite has dropped to 0ppm, dose back up to 4-5ppm. Again, you only re-dose when ammonia is 0ppm. When the ammonia and nitrite are getting to 0ppm in 24hrs, you can then start to test 12hrs after dosing. You are looking to get ammonia and nitrite down to 0ppm in 12hrs after dosing. At that point you can add fish but the general recommendation from experts on this forum is to to do a qualifying week where you get double zeros (ammonia & nitrite dropping to 0ppm) in 12hrs for 7 days just to be certain.

 

[OldMan47]

The "best practice" that we have generally settled on is that once the ammonia processors are present, you can keep them ticking over nicely with just a 2 ppm dose of ammonia. That keeps nitrite and nitrate levels from getting completely out of control before the next generations of bacteria have a chance to develop. Once you are trying to determine whether you are getting double zeros before 24 hours is plenty soon enough to raise that ammonia dose back up. At 4 or 5 ppm of ammonia, you are dosing more than any reasonable stocking in a tank will ever provide for your bacteria. The idea is that we would rather see some bacteria die off a bit due to lack of adequate supplies of ammonia than see them come up short once the tank is stocked and end up exposing the fish to ammonia or nitrites.