Keeping a non-cycled aquarium

kanzekatores
  • #1
This is something that kind has occurred to me when I try to explain the Nitrogen Cycle to people who don't understand the importance of it and are anxious to get fish. They find the easiest way out of having to wait a month and a half to start stocking, which is, just lightly stocking it and not cycling it at all.

In my experience, it takes a lot more than you'd think to get a cycle going; with such a big volume of water you need a lot of ammonia for it to be a significant ppm. So if you just keep one or two fish in a big tank, and for people that don't want to bite off more than they can chew and only get two fish, the ammonia's never going to go up enough for it to start the cycle. Is there anything wrong with just not cycling it, lightly stocking, and doing frequent water changes? Or will the cycle happen no matter if there's a lot of ammonia? Just curious.
 

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ProudPapa
  • #2
The problem might be in how you define "cycled". Without defining what the bioload will be the word is very vague. If a tank is ''cycled" it has a bacteria adequate to handle the current load, or a certain load if you're doing a fishless cycle. So the bacteria colony (that determines whether or not the tank is cycled) in a 55 gallon tank with a dozen mature mollies and two bristle nose plecos will be very different from one with just 5 neon tetras. Does that help, or even make sense?
 

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Joshaeus
  • #3
If there's any significant amount of ammonia, oxygen, and surface area in the tank, a nitrogen cycle (albeit not necessarily a very efficient one) will develop. However, almost all fish tanks have a much heavier bioload than most natural water bodies (which, in any event, do have functioning nitrogen cycles), and in the absence of a nitrogen cycle the ammonia will sooner or later reach lethal levels unless (A) VERY frequent water changes are performed, or (B) the tank has a robust population of plants (which frequently do not do well in the presence of large quantities of ammonia...some plants directly react badly to excessive ammonia levels, but the more serious problem is that ammonia is one of the primary algae triggers and an uncycled planted tank with any significant amount of ammonia will quickly become an unsightly algae soup. If you want a tank where ammonia is entirely dealt with by plants, it will really need to be prepared beforehand with a similar or greater amount of research and dedication as a typical cycle).
 
kanzekatores
  • Thread Starter
  • #4
Cycled to me meant that the first Nitrogen Cycle had happened, or else when you pour in live bacteria to your new tank, why would you have to wait for the first Nitrogen Cycle to happen, if it's already cycled?
Just in my experience, it took quite a while for my one freshwater tank to be tested and have any nitrates in the water, and my salwater tank still doesn't. I haven't experienced much of that ammonia build-up you're talking about myself. To me it seems like it takes a lot to start that first cycle, even disregarding water changes for a few weeks.
Couldn't you never have a BB colonization and simply keep a few small fish in a huge tank? Like those 5 neon tetras in a 55g? They would not have much bioload.
Forgive me I'm still a little bit confused on this stuff.
 
Joshaeus
  • #5
That would not be a lot of bioload, no...but it takes very little ammonia to harm fish. Wikipedia states; "At lower concentrations, around 0.05 mg/L, un-ionised ammonia is harmful to fish species and can result in poor growth and feed conversion rates, reduced fecundity and fertility and increase stress and susceptibility to bacterial infections and diseases. Exposed to excess ammonia, fish may suffer loss of equilibrium, hyper-excitability, increased respiratory activity and oxygen uptake and increased heart rate. At concentrations exceeding 2.0 mg/L, ammonia causes gill and tissue damage, extreme lethargy, convulsions, coma, and death. Experiments have shown that the lethal concentration for a variety of fish species ranges from 0.2 to 2.0 mg/l." For perspective, in a 55 gallon tank, .05 mg/L of total ammonia could be produced from less than a fifth of a gram (more accurately 0.15125 grams) of omega one freshwater flake food that was not eaten by the fish. At a PH of 7, this would include .0003 NH3 (un-ionised ammonia); granted, that is not very much...but how many of us have the precision to feed that little food to our fish in a day? The amount of NH3 in that ammonia sample increases with increasing PH.
 
kanzekatores
  • Thread Starter
  • #6
Wow this is really interesting I never knew this. My tanks would take forever to show any nitrates and there have been quite a few deaths over the years, so maybe it’s because of small amounts of ammonia. There’s so much emphasis on the nitrogen cycle when you start out but for me it’s such a rarity and I’ve only caught it happening once. It leaves me wondering about it how everyone is talking about it and I keep waiting for it to happen, testing all zeros.
So you couldn’t keep skip the nitrogen cycle because there’s always be small amount of ammonia, I’m assuming. I guess it makes sense but everyone’s normalizing ammonia, when I barely see it in my tanks. Maybe I need to add more pure ammonia in the first place instead of relying on the fishes’ bioload (which is not much). Thanks for the help
 

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Joshaeus
  • #7
No prob! It's still weird that you've had so much trouble getting a cycle going, though...
 
LightBrownPillow
  • #8
Wow this is really interesting I never knew this. My tanks would take forever to show any nitrates and there have been quite a few deaths over the years, so maybe it’s because of small amounts of ammonia. There’s so much emphasis on the nitrogen cycle when you start out but for me it’s such a rarity and I’ve only caught it happening once. It leaves me wondering about it how everyone is talking about it and I keep waiting for it to happen, testing all zeros.
So you couldn’t keep skip the nitrogen cycle because there’s always be small amount of ammonia, I’m assuming. I guess it makes sense but everyone’s normalizing ammonia, when I barely see it in my tanks. Maybe I need to add more pure ammonia in the first place instead of relying on the fishes’ bioload (which is not much). Thanks for the help

Do your tanks end up with regularly-increasing nitrate levels? If yes, then the nitrogen cycle is working, even if it is very small/slow due to light stock. Water changes for light stock may overwrite what your cycle does by just removing the ammonia before it is digested.
 
Momgoose56
  • #9
No prob! It's still weird that you've had so much trouble getting a cycle going, though...
Not really weird if the OP is using small numbers of fish. The fastest way to cycle a tank is to add 2-4ppm NH3 to an unpopulated tank, keep pH around 7-7.5,, temp around 78°F and feed ammonia to the tank up to 2 ppm any time it drops below 1 ppm. Make sure KH and GH are adequate and be patient. All tanks will cycle under those conditions.
 
kanzekatores
  • Thread Starter
  • #10
I think maybe the reason my freshwater 10g took such a long time to cycle is that I'm using a Aqueon Quietflow 10 filter, and the fish store convinced me to keep buying their cartridges to replace the dirty ones, me not knowing I was removing the bacteria by doing that.
I've decided for the saltwater tank to put in Dr. Tim's ammonia instead of relying on the fish. Hopefully then it will start the cycle.
 

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