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New tank - is my Nitrogen cycle established?

2K views 14 replies 7 participants last post by  Hallyx 
#1 ·
I recently started my first tropical aquarium. It's a 68L (15 Gallon) tank and I've had it up and running for 4 weeks (it is an Askoll Pure Large).

I've been using the API master test kit to test for Ammonia/Nitrate/Nitrite and I've always had a reading of 0 for all of them, does this mean that the Nitrogen cycle has been established? I have been advised that I may not see a spike during my first month.

I was advised by my local fish dealer to add fish after a week to speed up the nitrogen cycle. I added 6 guppies after a week and (not surprisingly) lost a few. A week later I added 2 dwarf gouramis and last week 8 diamond neon tetras.

Apart from the fish I have ~10 live plants, 3 pieces of bogwood (which I soaked prior to adding to remove the tannins) and some lava rock.

Are the readings 0 because I have bacteria? How likely is it I'd never see any of them reading above 0 during this time? If I should have seen above 0, is there another reason that I'm not seeing any of them registering?
 
#3 · (Edited)
How often have you tested the water over the past 4 weeks?

During the first week, before you added the guppies, did you add anything to provide an ammonia source (fish food, a piece of shrimp, ammonia)?

Right after the guppies died, did you check your water parameters?

As the tank cycles you should have received readings from the tests on your Ammonia, Nitrite and Nitrates.

With roughly 15 fish currently in the tank and readings of 0 it would seem that the tank has cycled, otherwise you'd see parameter readings or dead fish or both if the tank wasn't cycled.

However it seems puzzling to me that through the entire process you never encountered readings...

And I forgot something: WELCOME to the Tropical Fishkeeping Forum!
 
#8 ·
How often have you tested the water over the past 4 weeks?

During the first week, before you added the guppies, did you add anything to provide an ammonia source (fish food, a piece of shrimp, ammonia)?

Right after the guppies died, did you check your water parameters?
Thanks Tracy Bird. I didn't get my test kit until about 1.5 weeks after starting up the tank. Since then I've tested every other day for ammonia and roughly every 5 days for nitrite + nitrate.

Didn't add anything during the first week except plants etc, I was advised that adding fish would be fine (since read a lot of information to the contrary!).

Yes, after the first guppy died I took a water sample to my local supplier and they tested ammonia, nitrate, nitrite and PH. They said PH was a little high and the rest were 0 so they gave me a little starter bacteria to add in to help kick start everything.

However it seems puzzling to me that through the entire process you never encountered readings...
I'm confused myself. Everything I've read said I'd encounter spikes and it would eventually even out. I'm now not sure when to do water changes as I've read that it's best to wait until the cycle is established. Do you think it's safe to do a water change now (4 weeks after setting up)?
 
#5 · (Edited)
The usual way to tell is: if you're seeing a rise in nitrate every week, then your tank is cycled.

But, if you have enough plants, you may not even see this.
I've heard this before (although I've never experienced it)... and the original post does list 10 plants...

A lot of people, myself included, have to ADD nitrate to their tanks as the plants just eat it up....
 
#6 ·
Not all plants are equal in ammonia-processing. Ten Anubias or Java fern is not the same as ten Watersprite or Hornwort.

The end result of a functioning nitrogen cycle is nitrate. Depending on stock, this should increase measurably between weekly pwc's.

Plants mostly eat ammonia, so nitrates never occur. I can't imagine adding nitrates for any reason. Why are you doing that?
 
#9 ·
My last tank also didn't really spike eitherand I think it was due to using some "dirty water" from another aquarium filter and that it was heavily planted. Sounds like you may be experiencing the same thing.

After 4 weeks you should be ok to do a water change. Nonetheless, I'd keep monitoring ammonia and nitrite levels.
 
#10 ·
Using dirty water does nothing much more than transfer dirty water as the micro organisms are adhered to the various surfaces in the tank creating a biofilm, not free floating in the water. While there may be some stragglers that do get transferred, they are not enough to make any significant difference in the cycling process.

With 10 plants, even the plants that you have, if you haven't added a bunch of ammonia directly, you could expect to see little to no spiking in ammonia and little to no spiking of nitrites either. Also, the nitrates will build up much more slowly as the plants circumvent the whole cycle by absorbing ammonia before it gets oxidized into nitrite and will use some amount of nitrate on the backside. I have yet to test anything over 5ppm nitrate in one tank even after extended periods between water changes. Some higher energy tanks (lots of light, CO2 injection and fertilization) will run dry of nitrates as well... as mentioned already.

The idea behind not doing water changes during a cycle is to maximize the amount of ammonia concentration for the ammonia oxidizers... which is counter productive if you are in a hurry or trying to do a fish in cycle.

As soon as there are fish involved, water changes should commence:

- If levels are measurable, then every day or two while using a conditioner like Prime that renders the ammonia and nitrites non-toxic to the fish.This allows the fish in cycle to provide ammonia to the growing micro organisms while protecting the fish from the effects of the toxins.

- If levels are not measurable then whatever your schedule may eventually be.

Doing changes will not stall or affect the cycle if there is a regular source of ammonia production in the tank (fish and fish waste). In pure ammonia cycling you are effectively bringing the concentration up by adding ammonia and in that case changing the water is only advisable if the concentration reaches or exceeds 1ppm.

Jeff.
 
#12 ·
Yes, I agree. To capture any of the beneficial bacteria, you need to extract some of it from filter media from the established tank. Water transfer alone won't work. It seems to help jump start the new tank cycling process for me, once the other factors are in play (e. g. ammonia source)
 
#13 ·
Hey Jeff! I don't understand your statement about doing WC if the ammonia goes above 1 ppm. I don't remember where I saw it, but he instructions for fishless cycling said that you need to get the Ammonia to 4 ppm and keep it there until you get nitrite. I'm not arguing just trying to understand. Thanks.
 
#14 ·
The entire cycle, ammonia oxidizers and nitrite oxidizers, establishes at its most efficient rate when the ammonia, and ideally nitrite, are below 1ppm. The nitrite oxidizers remain dormant at levels of ammonia beyond that so, while 4ppm will work for the ammonia oxidizers it stalls the second stage of the cycle.

I was able to get a cycle established in 7 days, another member here managed 9 days using the same 1ppm guide and I talked to a waste water management tech, they set up very large scale cycles in 7 days as well. There is no reason to wait weeks and months to establish a cycle using high ammomia levels when just lowering that concentration produces a cycle that can take as little as 7 days.

The point is, a WC at 1ppm or higher just lowers the concentration and accelerates the cycle.

Jeff.
 
#15 · (Edited)
The ppm of ammonia is a matter of opinion and experience. I've cycled tanks in 10 days with 6.0ppm ammonia. The amount of starter bacteria effects the timing in that bacteria doubles every day or so. So achieving a cycle with a low ammonia-processing capacity should take less time.

If you're stocking shoals of fish at one time, I would think you'd want that capacity to be much higher, perhaps as high as 4.0ppm/day. Of course, if you're only stocking one fish and a shrimp, I guess less would do.
 
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