trouble with fishless cycle

[Lady Hobbs]

I have to agree with a couple others here. You are dosing your 26 gallon the amount used to cycle a 55 gallon. You could have started with ammonia levels of 2 and when you began to see nitrites, dropped it to only 1 when dosing ammonia. It doesn't matter if it drops to 0 in 6 hours or 15 hours. You still only dose one time per day.

On a larger tank, you have more filtrating. The more filtering you have, the more room you have to grow a bunch of bacteria. A smaller filter does not allow those big amounts of bacteria.

Read the cycling threads.

[pckroeger]

I'm a little confused. Can someone please explain the reason why a smaller tank should use lower ppm concentrations of ammonia than large tanks? because to me, the recommended concentration used for fishless cycling could and should be the same for any size of tank, because 4ppm of ammonia in a 55g tank is a lot more ammonia than 4ppm in a 10 gallon tank and will therefore grow more bacteria. concentration is a ratio of ammonia to water so shouldn't it be the same for any tank size? my 26g tank has less water, a smaller filter, and requires less beneficial bacteria than a 55g, but 4ppm ammonia in my tank would be a lot less ammonia than 4ppm in a 55g, so can someone explain the reason why the concentration would need to change with the size of tank??
apologies if this is a stupid question, i just cant get my lil old head around it, thanks!

[pckroeger]

UPDATE: the ammonia finally dropped down to 0, and just in time as my nitrites dropped to 0 yesterday, phew!
I will leave it until tomorrow to redose, just to make sure it's definitely 0, and if it is 0 tomorrow i will redose to 1ppm as recommended by you guys, and to avoid the suboptimal nitrification that myofibroblast suggested.
thanks so much for all the help guys!

[Cermet]

Lady Hobbs is correct.

Aside: pc kroeger - you are absoultly correct. The amount of ammonia for a 50 gal tank to achieve 1 ppm is double what a 25 gal tank has when also dosed to 1 ppm. Also, and importantly, the available bio media in the filter is also bigger (more surface area) for a bigger tank filter (if you get the proper filter for the tank size, of course.) Again, in the peer reviewed research paper I read, 1 ppm ammonia worked best for any tank size. I see no issue with 2 ppm, or even 3 ppm (esp. relative to growing bacteria that consumes ammonia) but as you do go higher in ammonia levels, this can cause problems with the bacteria growth that convert nitrites.

[pckroeger]

I would not wait until tomorrow to redose the level to 1 ppm; the bacteria will starve if you wait two days before feeding; this could wipeout much of the newly grown bacteria! Feed when ever you measure zero ammonia after 24 hours.

Thanks for the save! i owe you one

[Honey Badger 1]

the recommended concentration used for fishless cycling could and should be the same for any size of tank, because 4ppm of ammonia in a 55g tank is a lot more ammonia than 4ppm in a 10 gallon tank and will therefore grow more bacteria.

You are correct. 4ppm will convert in a small tank just as well as it will in a large tank, but it isn't needed. Small tanks have small fish and smaller bio-loads, so starting with less ammonia is recommended. There has been some talk here that smaller filters won't hold enough bacteria to process 4ppm ammonia, but I have never had any issues with my smaller tanks and have never found any scientific research to back this up. Now, if you were to add ammonia that is too high for your API testers to register then you will kill off everything and the tank won't cycle, but 4ppm is not so high that will happen in any size tank.

[Honey Badger 1]

Again, in the peer reviewed research paper I read, 1 ppm ammonia worked best for any tank size.

Where is this peer reviewed paper. I have cycled tanks quickly with much higher doses of ammonia, and many people here have cycled quickly with much higher doses of ammonia. You often talk about this peer reviewed paper, but I have asked you for it many times and never get an answer.

[myofibroblast]

...4ppm ammonia in my tank would be a lot less ammonia than 4ppm in a 55g, so can someone explain the reason why the concentration would need to change with the size of tank??
apologies if this is a stupid question, i just cant get my lil old head around it, thanks!

pckroeger, I'm very glad to hear your ammonia has finally come down to zero. Bacteria are a hardy bunch, they will work themselves out! :-)

I'd just like to congratulate you on stating clearly the difference between AMOUNT and CONCENTRATION. As a beginner, reading posts where individuals talk about high amount just means more growth really makes me cringe. To speak of these terms so loosely becomes scientifically dishonest, and really does mislead people into validating misleading hypotheses.

For example: Lets say the environmental nitrifying bacteria you are starting with is 10 bacteria/cm2 of substrate surface. Utilization of substrate (such as ammonia) by organisms is dependent on CONCENTRATION rather than AMOUNT. The bacteria will not give 2 cents about how many milligrams of ammonia is present in the entire tank. If the bacteria carries out 2 binary divisions (which is the way nitrosonomas proliferates, splitting from one bacteria to two bacteria) in 24 hours at 4ppm of NH3, but can only carry out 1 binary division in 24 hours at 1ppm NH3, then at the end of the day, regardless of the size of your tank, you will reach a population density of 40 bacteria/cm2 of substrate if you use 4ppm, and only 20 bacteria/cm2 of substrate if you use 1ppm. The change in density is, therefore, solely dependent on concentration and not amount. To suggest otherwise leads to some murkiness in thought and explanation.

Hence, when people loosely talk about "too much" bacteria for a smaller substrate when using 4ppm in a small tank, they really need to be clear about whether they are implying the bacterial DENSITY is too high or just overall bacteria count is too high. Obviously, a larger tank, at the same bacterial density, will have a larger number of bacterial because it has larger surface area. But I suspect the ability for ammonia-oxidizing bacteria to convert a certain concentration of ammonia (again in ppm) is better correlated with bacterial DENSITY rather than bacterial number.

As far as Cermet's comment regarding whether 4ppm is too high or not, I think it's certainly possible that you reached critical density with 4ppm, whereas you may not have if you had just used 1ppm. However, we cannot surmise whether this would not have been the case had you used a 55g tank, however, because you never did the experiment. For all we know, you could be experiencing the same problem in a larger tank with 4ppm of ammonia.

You will read many anecdotal evidence (hence forum) here about people with variable success using anything from 1-5ppm of ammonia in variously sized tanks. Cycling is not an exact science, and everyone does it differently no matter how much people here try to prescribe a regime. Local water conditions, temperature, dissolved oxygen, pH, etc. are different and all affect both the rate at which bacteria divides as well as their enzyme production and efficiency (in this case the enzymes responsible for ammonia oxidation).

I do hope that we beginners can go into creating a biotope with certain basic concepts (such as really helpful readings about fishless cycling sticky'd in this forum or others), and when we experience unexpected results (i.e. NH3 hovering around 0.25ppm even though there is abundantly clear evidence that ammonia-oxidizing bacteria are present) we can formulate some hypotheses, proceed with a course of corrective measure (and sometime it's as simple and inexpensive as waiting), and then have a framework with which to analyze the results be it expected or unexpected. The alternative is to do blindly what others tell you to do, but once you have an unexpected outcome, you may not know how to handle it or have a framework to evaluate suggestions from other people. It would kind of like taking your local fish store staff's word as gospel, no matter how correct or incorrect they are.

[Lady Hobbs]

Cycling is not a huge scientific project and needs not be turned into one. Keep it simple and it will end up being simple.

Fish expel ammonia from their gills, waste and the food they are given. Cycling a tank with ammonia simply takes that strain of survival off the fish if done before hand. When we cycle with ammonia, we are growing far more ammonia than is needed to produce the required bacteria for the stock in the tank. It's a great method and allows us to stock more fish right off the bat rather than starting with just a few and keeping up with constant water changes.

But, we have to remember, too, that the filter on the tank can only handle just so much bacteria. In a large tank, there is more filtration with a huge area for bacteria to thrive. Obviously in a small tank, we have a filter to fit that tank size. If you had a 26 gallon tank with a couple canister filters on it, then obviously dosing a higher dose of ammonia is no problem. It's not the volume of water that determines the amount of ammonia but the filter that's on that smaller tank.

Glad to see you have gotten your cycle. Congrats.

[Lady Hobbs]

myofibroblast.....No one here is trying to "prescribe a regime". We have been helping people here for a long time with stalled cycled, or cycles that have gone on far too long and we know what works and what does not.

Obviously, every cycle is a bit difference with different types of water, different oxygen levels, different temps but all work pretty much the same. In almost every case that a problem arises or a cycle is taking too long, it's due to ammonia levels too high for the filter size, ammonia levels not dropped off when nitrites are present, dosing ammonia more than once a day, etc.

Too much ammonia causes more problems than too little ammonia.