When Is A Cycle Finished?

[iankent]

Have we reached any consensus here? My perusal leads me to feel that the participants have re-validated the 5ppm targeting concentration as a reasonable number having a little cushion and giving the beginner a good starting point for stocking, even if the stocking is close to beginner max.

I think so yeah, I'd like to see some more opinions/evidence regarding the second stage of cycling, getting rid of the nitrite. I'm thinking if you do a massive water change when your ammonia first drops to 0ppm in 12 hrs (cos at this point you'll have a fair build up of nitrite) then the NBacs can start fresh as it were and just process the nitrite from the daily 5ppm of ammonia rather than the whole backlog of nitrite. Then if it takes a week or so for the nitrite to start dropping maybe clear the backlog again.........

I want somewhere to set up another tank to tinker around with a fishless cycle!!!

I agree too, I've had a look around the net and rdd's article in particular seems to be the most completely up to date one I've found!

MW - as it happens, I might be able to find a bit of space and time to try some things out - any suggestions on any cycling experiments worth doing? on my list at the moment is:
* Does clearing the backlog of nitrites speed up cycling? (Without reducing ammonia levels)
* Will increasing volumes of ammonia throughout the cycle work faster than constant higher levels (e.g., starting off with 0.5ppm and waiting for a 0, then moving to 1ppm and waiting for 0, rather than pushing to 5ppm every time)
* Will adding ammonia in small quantities regularly work better than large amounts once a day (the drip-line idea)

If I can find enough room, I'm intending to try each of those at different temps/pH levels (unfortunately, testing two pH levels at a time instead of 1 doubles the space I need )

edited to add: my intention would be to start with fully sterile equipment, introducing bacteria purely via tap water (this should help ensure the starting bacteria count is roughly the same in each!), and keeping the temps/pH stable, which hopefully will let us make a decent comparison of the results at the end!

 

[Miss Wiggle]

ooooh yay for experiments,

well one of the things I wanted to know is when you've reached the point in a cycle where the last little bit of nitrite (like 0.25ppm) just won't shift, is it then safe to do your big water change and stock the tank. Stormy just tried this and has had no ammonia or nitrite since stocking, however he's only stocked the tank to about one third full because a lot of the fish he wanted aren't suitable for a newly cycled tank. I'd like to see what happens if you fully stock at that point but just stick to hardy fish, danios and platy's or something like that. Obviously the only situation I'd want someone to try this in is if they have mature media on hand so if there is a blip of nitrite or ammonia it can eb rectified so the fish are not at risk.

should do a control too for comparison, following the instructions of rdd's add & wait method post to the letter.

if you can tinker with the pH so one is at something like 6 and one is up at 8 I'd be interested to see the real difference in speed.

oooh and also, there's a theory that if the pH drops below 5.5 a different species of ammonia consuming bacteria will grow but it grows much slower, I'd like to see someone try to cycle a tank at that pH.

ummmmmmmmm i'll probably think of more things to try later.............

 

[waterdrop]

Have we reached any consensus here? My perusal leads me to feel that the participants have re-validated the 5ppm targeting concentration as a reasonable number having a little cushion and giving the beginner a good starting point for stocking, even if the stocking is close to beginner max.

I think so yeah, I'd like to see some more opinions/evidence regarding the second stage of cycling, getting rid of the nitrite. I'm thinking if you do a massive water change when your ammonia first drops to 0ppm in 12 hrs (cos at this point you'll have a fair build up of nitrite) then the NBacs can start fresh as it were and just process the nitrite from the daily 5ppm of ammonia rather than the whole backlog of nitrite. Then if it takes a week or so for the nitrite to start dropping maybe clear the backlog again.........

I want somewhere to set up another tank to tinker around with a fishless cycle!!!

I agree too, I've had a look around the net and rdd's article in particular seems to be the most completely up to date one I've found!

MW - as it happens, I might be able to find a bit of space and time to try some things out - any suggestions on any cycling experiments worth doing? on my list at the moment is:
* Does clearing the backlog of nitrites speed up cycling? (Without reducing ammonia levels)
* Will increasing volumes of ammonia throughout the cycle work faster than constant higher levels (e.g., starting off with 0.5ppm and waiting for a 0, then moving to 1ppm and waiting for 0, rather than pushing to 5ppm every time)
* Will adding ammonia in small quantities regularly work better than large amounts once a day (the drip-line idea)

If I can find enough room, I'm intending to try each of those at different temps/pH levels (unfortunately, testing two pH levels at a time instead of 1 doubles the space I need )

edited to add: my intention would be to start with fully sterile equipment, , introducing bacteria purely via tap water (this should help ensure the starting bacteria count is roughly the same in each!), and keeping the temps/pH stable, which hopefully will let us make a decent comparison of the results at the end!

Interesting you should mention this:
", introducing bacteria purely via tap water (this should help ensure the starting bacteria count is roughly the same in each!),"

as I often think, while we are helping each other and beginners over in the "New" forum, that two of things always creating the "push" to know more about whether we can speed up fishless cycling are:
1) Impatience - Despite having shown some good articles of why one might expect an average process to take 21 days (I believe Bignose had an article about that that most of us remember), just about every newbie starts whining at about 5 days or so
2) The tendency to think that tap water is starting raw fishless cyclers from the same starting point: I keep wondering if there might not be enough variation in whether, across different people in different places, that new tank of tap water and ammonia is initially seeing zero, two, or 2000, for example, inoculants of desired bacteria from the air or from chlorine resistance or wherever it comes from! That initial appearance of the correct species, its timing, could have a leverage effect on the overall time that fishless cycling takes I would think (unless the exponential nature of the later growth curve just wipes out this effect (Bignose?))

~~waterdrop~~
ps. I also (remind me later) still want to discuss the pH thing more... Don't you find yourselves wondering, if we could magically have the data compiled from all our various fishless cyclers over the world, whether a trend would immediately fall out showing a bell curve around some optimal and fastest pH, like 8.0 or something, and we would realize that forcing the incubation water to that pH would improve everyone's cycle?

 

[Miss Wiggle]

Interesting you should mention this:
", introducing bacteria purely via tap water (this should help ensure the starting bacteria count is roughly the same in each!),"

as I often think, while we are helping each other and beginners over in the "New" forum, that two of things always creating the "push" to know more about whether we can speed up fishless cycling are:
1) Impatience - Despite having shown some good articles of why one might expect an average process to take 21 days (I believe Bignose had an article about that that most of us remember), just about every newbie starts whining at about 5 days or so
2) The tendency to think that tap water is starting raw fishless cyclers from the same starting point: I keep wondering if there might not be enough variation in whether, across different people in different places, that new tank of tap water and ammonia is initially seeing zero, two, or 2000, for example, inoculants of desired bacteria from the air or from chlorine resistance or wherever it comes from! That initial appearance of the correct species, its timing, could have a leverage effect on the overall time that fishless cycling takes I would think (unless the exponential nature of the later growth curve just wipes out this effect (Bignose?))

~~waterdrop~~
ps. I also (remind me later) still want to discuss the pH thing more... Don't you find yourselves wondering, if we could magically have the data compiled from all our various fishless cyclers over the world, whether a trend would immediately fall out showing a bell curve around some optimal and fastest pH, like 8.0 or something, and we would realize that forcing the incubation water to that pH would improve everyone's cycle?

yeah i've heard of people trying to fishless cycle and absolutley nothing happening, then doing a big water change and it all kicks off and I've thought were there just no bacteria in the first lot of water, nothing to even get started with. I'm sure the levels must fluctuate from sample to sample and from water authority to water authority.

yeah definatley curious about how much pH affects cycling, in an ideal world it'd be nice to run several cycles at the same time from the same water to start off each cycle having a pH difference of .1 and seeing how they all run.

 

[rdd1952]

Yeah i've heard of people trying to fishless cycle and absolutley nothing happening, then doing a big water change and it all kicks off and I've thought were there just no bacteria in the first lot of water, nothing to even get started with. I'm sure the levels must fluctuate from sample to sample and from water authority to water authority.

I've been following this and there is some really interesting stuff on it. I started with some experiements a while back but it's difficult to do everything that you want. And, as mentioned, sometimes a cycle just stalls. In one of my past experiments, I had a tank go 18 days with no change at all in the first ammonia. It never dropped and there was never any nitrite. Did that mean there weren't any bacteria in the original water? It's unlikely that our drinking water is that "pure". I never figured out what happened.

I think to really do a good experiment, you really need room (and money) to set up at least 3 to 5 tanks, side by side and fill them at the same time so that you know they have the same water and same atmospheric conditions. Unfortuately, that is difficult to do in our homes. I certainly don't have the ability to do it. And if course, if you wanted to conduct a full slate of cycling experiments, you would also need a lot of time as there are so many different things you can test: effects of varying pH (would be difficult to keep the pH stable since the rising nitrate has an effect on it), different filter types, bacteria-in-a-bottle products, temperature, water changes or not during the cycle (I seriously think that they would help once the nitrite has gone off the chart), planted vs. no plants, substrate vs. no substrate, large tank vs. small tank, etc. Of course, if you were just experimenting on the different ways to actually do a fishless cycle, there are plenty of those too.

 

[LionessN3cubs]

This really does make interesting reading. As MW and BTT know my tank has been cycling for my tank for 42 days so today is the end of week 6. The 4.00ppm ammonia is clearly processing easily within 12 hours however the NitrIte is taking a while to process and having tested it every hour last night it looks like it is processing within 17 hours. Im at the point now of trying to decide whether to mid stock the tank, eg 6 apistogramma's and 15-20 Rummy Nose Tetra's or carry on adding ammonia until both ammonia and nitrIte are processed within the 12 hours. This thread has swayed me more towards stocking the tank tomorrow but the last thing I want to do is harm any fish I add to the tank. As BTT and MW have pointed out its a judgement call..... I wish I had the time to add the ammonia every hour to raise it by 0.5ppm (thats about 0.9ml in my tank with homebase ammonia) to be sure it could handle the load...... I'm really not sure what to do.....

Stormy ...we're both at about the same point. My Nbacs are processing Nitrite in roughly 17 hours as well. I wonder what would happen if we cut the ammonia we're adding in half (since 4ppm is way more than the 1/2 stocking bioload adding fish would give) and test it out in 12 hours then?

 

[Miss Wiggle]

stormys gone on to stock his tank (albeit lightly) and has had 0 ammonia and nitrite since, been maybe a week now like that so looks stable.

Not to say your definatley ready for fish yet but it's a consideration.

 

[LionessN3cubs]

My cycle just doesnt want to finish plain and simple..I've decided that its never going to.

Right now at the 12 hours mark...I still have a full 1ppm of nitrite. It IS getting closer..I mean 2 weeks ago at 24 hours I still had 1ppm or more...now its down to 0 in 17 hours. I just can't get it any closer. Im also wondering if a lack of a light source is a factor? Do the Nbacs need more than room lighting to grow? Im excepting something to happen any day now that will set me back...which is what has happened both of the 2 other times I got to this point argh!

 

[Miss Wiggle]

Nah the light shouldn't have any effect, if you think about it, in a canister filter the bacteria is entirley in the dark.

it'll happen Lioness. I know it's taken a lot of patience to get where you are, but it is getting there slowly but surley

 

[iankent]

ooooh yay for experiments,

well one of the things I wanted to know is when you've reached the point in a cycle where the last little bit of nitrite (like 0.25ppm) just won't shift, is it then safe to do your big water change and stock the tank. Stormy just tried this and has had no ammonia or nitrite since stocking, however he's only stocked the tank to about one third full because a lot of the fish he wanted aren't suitable for a newly cycled tank. I'd like to see what happens if you fully stock at that point but just stick to hardy fish, danios and platy's or something like that. Obviously the only situation I'd want someone to try this in is if they have mature media on hand so if there is a blip of nitrite or ammonia it can eb rectified so the fish are not at risk.

my intention initially is to do everything without any live animals - after "cycling" i'll just add ammonia again to test how cycled it is - working on a way I can measure the ammonia levels my fish are producing throughout the day!

should do a control too for comparison, following the instructions of rdd's add & wait method post to the letter.

if you can tinker with the pH so one is at something like 6 and one is up at 8 I'd be interested to see the real difference in speed.

oooh and also, there's a theory that if the pH drops below 5.5 a different species of ammonia consuming bacteria will grow but it grows much slower, I'd like to see someone try to cycle a tank at that pH.

not sure I'm going to have the space for all these but I'll see what I can do!! as for the control, I'm going to cycle my quarantine tank following rdd's add and wait instructions word for word! (getting it tomorrow, so can get started on that bit quite quickly!)

 

[iankent]

Interesting you should mention this:
", introducing bacteria purely via tap water (this should help ensure the starting bacteria count is roughly the same in each!),"

as I often think, while we are helping each other and beginners over in the "New" forum, that two of things always creating the "push" to know more about whether we can speed up fishless cycling are:
1) Impatience - Despite having shown some good articles of why one might expect an average process to take 21 days (I believe Bignose had an article about that that most of us remember), just about every newbie starts whining at about 5 days or so

lol, patience is the big part of the problem but i'm sure there's ways we can speed things up - there has to be room for improvement here

2) The tendency to think that tap water is starting raw fishless cyclers from the same starting point: I keep wondering if there might not be enough variation in whether, across different people in different places, that new tank of tap water and ammonia is initially seeing zero, two, or 2000, for example, inoculants of desired bacteria from the air or from chlorine resistance or wherever it comes from! That initial appearance of the correct species, its timing, could have a leverage effect on the overall time that fishless cycling takes I would think (unless the exponential nature of the later growth curve just wipes out this effect (Bignose?))

all of your water stats will change over time, from bacteria levels to ph - while they may not vary too much most of the time, even a change from 10 bacteria/litre to 200 bacteria/litre is a huge jump in terms of cycling (and the bacteria that are there might be dead when they arrive anyway!) time to do lots of research into bacteria i think

~~waterdrop~~
ps. I also (remind me later) still want to discuss the pH thing more... Don't you find yourselves wondering, if we could magically have the data compiled from all our various fishless cyclers over the world, whether a trend would immediately fall out showing a bell curve around some optimal and fastest pH, like 8.0 or something, and we would realize that forcing the incubation water to that pH would improve everyone's cycle?

see www.my-aqua.net - a project i've been working on (just click my signature). it allows you to record water test results for each aquarium you own (as well as lots of other stuff ), but with some fine tuning and enough members we should be able to get partially useful data! (unfortunately any data we could collect this way would be limited by how well each individual can read their test results!)

as for the pH, it almost certainly makes a difference, but it'll take a lot of data/testing to work it out exactly (plus the effect of pH might be changed further by the effect of temperature/bacteria/minerals/ammonia/chlorine etc., further complicating things!) all we can hope to do is improve the efficiency of the cycle a little bit, and once we've done that, try to improve it again (even then, the improvements still wont work for everybody!)

 

[iankent]

I've been following this and there is some really interesting stuff on it. I started with some experiements a while back but it's difficult to do everything that you want. And, as mentioned, sometimes a cycle just stalls. In one of my past experiments, I had a tank go 18 days with no change at all in the first ammonia. It never dropped and there was never any nitrite. Did that mean there weren't any bacteria in the original water? It's unlikely that our drinking water is that "pure". I never figured out what happened.

It could be possible that the drinking water is pure - if the water supply is filtered and cleaned extremely well (either using light or O3 etc.), then the chlorine in the water might kill those last few bacteria before it gets to your tap. unlikely, but possible (and could it be possible that adding 5ppm ammonia to the tank kills the bacteria if its only there in tiny numbers?) - by collecting enough cycling data and hopefully getting plenty of tests done, we might be able to narrow down some reasons as to why a cycle stalls... hopefully

I think to really do a good experiment, you really need room (and money) to set up at least 3 to 5 tanks, side by side and fill them at the same time so that you know they have the same water and same atmospheric conditions. Unfortuately, that is difficult to do in our homes. I certainly don't have the ability to do it. And if course, if you wanted to conduct a full slate of cycling experiments, you would also need a lot of time as there are so many different things you can test: effects of varying pH (would be difficult to keep the pH stable since the rising nitrate has an effect on it), different filter types, bacteria-in-a-bottle products, temperature, water changes or not during the cycle (I seriously think that they would help once the nitrite has gone off the chart), planted vs. no plants, substrate vs. no substrate, large tank vs. small tank, etc. Of course, if you were just experimenting on the different ways to actually do a fishless cycle, there are plenty of those too.

as you say, there are so many experiments that could be done, but its having the space, time and money!! I'm hoping to have space for 10 at a time (the tanks wont be huge anyway), but we'll have to see

of course, if anyone wants to do some experiments too that'd be great. maybe I could get something setup on my website for keeping track of who's doing what and what results we're all getting?

*quits work to devote his life to science and fish!*

 

[rdd1952]

I'm hoping to have space for 10 at a time (the tanks wont be huge anyway), but we'll have to see

That is an experiment in itself. Do larger tanks cycle faster or slower? To me, it would seem to make sense that a smaller tank would cycle faster. For argument sake, say it takes 1 million bacteria to process 1 ml of ammonia in 12 hours. In a 5 gallon tank that is roughly 5 ppm. In a 50 gallon tank though, 5 ppm would be 10 ml so it would take 10 million bacteria to process it. Thus meaning that the bacteria colony would have to double 3 more times (roughly 3 more days) from 1 million to get to over 10 million. But it would seem that most people say that smaller tanks take longer.

 

[iankent]

That is an experiment in itself. Do larger tanks cycle faster or slower? To me, it would seem to make sense that a smaller tank would cycle faster. For argument sake, say it takes 1 million bacteria to process 1 ml of ammonia in 12 hours. In a 5 gallon tank that is roughly 5 ppm. In a 50 gallon tank though, 5 ppm would be 10 ml so it would take 10 million bacteria to process it. Thus meaning that the bacteria colony would have to double 3 more times (roughly 3 more days) from 1 million to get to over 10 million. But it would seem that most people say that smaller tanks take longer.

well I think you've got me stumped with that!

the only explanation I can think of is that a difference of 3 days is on the edge of statistical validity, and with cycles ranging from a week to 2 months or longer, and so many other variables, that it might be down to something else and water volume itself is having a relatively minor difference. there would possibly be a more noticeable difference if we were looking at a 100L and a 10000L because that would take a few extra weeks, but I'm not sure 3 days means too much.

if we could get plenty of reliable test data covering a wide range of factors, we might be able to identify some other patterns that could explain it

 

[iankent]

have a theory for a way to measure your ammonia and nitrite readings in a fully cycled tank (i'm assuming here that there will be near constant production of ammonia and nitrite as food/waste decays over time)

take 1L of your tank water - as we know its between 0 and 0.25 (probably nearer 0), and as our tests can read upto 5ppm, we need to make it 20 times more concentrated. leave your tank water (or very gently heat it) until you have 50ml of liquid left. measure with your test kit and divide the result by 20!

as it'll be pretty difficult to work out when you've got 50ml left, it's probably easier to get it between 25ml and 100ml, measure what you have left, and then recalculate the ratio and divide by that instead! (i.e., with 50ml left, a reading of 5ppm is 0.25ppm in your tank, and a reading of 1ppm is approx 0.05ppm in your tank)

i doubt it'd be amazingly accurate, and I haven't tested it out yet, but am going to now and will let you know what my reading is!