Am I Missing Something About The Nitrogen Cycle?

Lauryn

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I started tropical fish keeping this summer, initially I was using tetra test strips however I soon came to realise I was getting false readings. I changed and stated testing water with the API master test kit however the false reading now put me in the position of doing a cycle with fish. I was changing 40-50% water daily and dosing with prime.

After getting a consistent reading of PH 8.2, Ammonia 0, Nitrite 0 and Nitrate 5-10 using the API master test kit I considered my tank to be fully cycled 31st August, nevertheless I continued doing water changes a min of twice a week and was adding a daily dose of prime to the tank.


For my last 2 water test reading I got the following:

02nd September - PH 8.2, Ammonia 0.25, Nitrite 0 and Nitrate 5-10

08th September - PH 8.2, Ammonia 0.25, Nitrite 0.25 and Nitrate 0

I am really unsure why I am getting these ammonia, nitrite and nitrate readings, there has been no change to the tank since 31st August – no new fish, same amount of food. Does this mean my tank has not cycled? What should I be doing now?
 

Skavatar

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ammonia readings can be +- 0.25

my 75g has been like that since i set it up. my 29g which has been cycled for over a year, and once in a while i'll get that .25 reading. annoying but nothing to worry about. you don't have to dose Prime every day, since its good for up to 48hrs.
 

GuppyDazzle

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From your numbers it looks like something broke your cycle, it's often called a "mini-cycle." Did you do a deep clean? Bacteria form on surfaces, so if you clean everything at once, you'll reduce the bacteria colony. In that case it doesn't destroy the bacteria colony, but it will take a few days to bounce back.

Are you using bottled bacteria? That will send your test readings wacky.

A fish-in cycle is fine as long as you test frequently and do water changes to keep the toxin levels down. Add your readings for ammonia and nitrites, and keep the number at 1 ppm or below.

Make sure you follow instructions for bottle #2 of the nitrate test. Shake the indicator solution for 30 seconds before adding to the test tube, then shake the test tube for 60 seconds, wait five minutes for the reading.
 

Momgoose56

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In addition to the others statements: your filter media containers the bulk of the most functional nitrifying bacteria. If you remove filter media, you are throwing away that most effective bacteria in your tank and that will disrupt your cycle (especially in a newly cycled tank). If you are regularly replacing filter media (as most filter manufacturers suggest), stop doing that. Instead, rinse the filter media thoroughly in drained tank water or fresh dechlorinated water with every water change and reuse it until it wears out. Once you buy a filter, the manufacturer's only keep making money if they keep selling you filter cartridges. The only thing that really needs to ever be replaced in those cartridges is the carbon. And you only really need carbon (in a cycled, well maintained tank) to remove residual medication after treatment.
 
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Lauryn

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86 ssinit said:
The ammonia reading may be false. Try testing your tap water with all tests. How are the fish? Nitrate is common and fine up to 40ppm. Than do a water change.

What size tank and filter?
I have a 54l tetra starter tank, it came with heater, lights and filter, unfortunately I have no idea what filter size/speed it is.

The fish all appear to be fine, eating well, no difficulty swimming, no gasping for air, no fuzzy bits.

Regarding the nitrates it's more that they suddenly disappeared.

I have just tested my tap water and got the following readings
PH 7.6
PH (high range) 8
ammonia 0.25
Nitrite 0
Nitrate 0

Skavatar said:
ammonia readings can be +- 0.25

my 75g has been like that since i set it up. my 29g which has been cycled for over a year, and once in a while i'll get that .25 reading. annoying but nothing to worry about. you don't have to dose Prime every day, since its good for up to 48hrs.
Thanks Good to know others have this issue as well

GuppyDazzle said:
From your numbers it looks like something broke your cycle, it's often called a "mini-cycle." Did you do a deep clean? Bacteria form on surfaces, so if you clean everything at once, you'll reduce the bacteria colony. In that case it doesn't destroy the bacteria colony, but it will take a few days to bounce back.

Are you using bottled bacteria? That will send your test readings wacky.

A fish-in cycle is fine as long as you test frequently and do water changes to keep the toxin levels down. Add your readings for ammonia and nitrites, and keep the number at 1 ppm or below.

Make sure you follow instructions for bottle #2 of the nitrate test. Shake the indicator solution for 30 seconds before adding to the test tube, then shake the test tube for 60 seconds, wait five minutes for the reading.
Once a week I use a sponge to wipe the inside of the tank. I did rinse the filter in the old tank water for the first time since I set up the aquarium, but I thought that's what you were supposed to do

I'm not using any bottled bacteria

I do shake the bottles, maybe I'm not shaking enough.

Fish keeping is a lot more complex than I originally thought

Momgoose56 said:
In addition to the others statements: your filter media containers the bulk of the most functional nitrifying bacteria. If you remove filter media, you are throwing away that most effective bacteria in your tank and that will disrupt your cycle (especially in a newly cycled tank). If you are regularly replacing filter media (as most filter manufacturers suggest), stop doing that. Instead, rinse the filter media thoroughly in drained tank water or fresh dechlorinated water with every water change and reuse it until it wears out. Once you buy a filter, the manufacturer's only keep making money if they keep selling you filter cartridges. The only thing that really needs to ever be replaced in those cartridges is the carbon. And you only really need carbon (in a cycled, well maintained tank) to remove residual medication after treatment.
Thanks for the response; On Saturday I did dunk the filter in the old tank water for the first time since I set up the aquarium. Could it be that as it was newly cycled this still washed away the bacteria?

I tested the aquarium water again tonight and got the following reading:
PH 8.2
ammonia 0.25
Nitrite 0
Nitrate 5

I guess I'll keep monitoring to see if anything changes
 

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86 ssinit

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Your good your reading are good. Looks like the ammonia is giving you a false reading. Nitrates are fine. You should have nitrates.
 

Momgoose56

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Lauryn said:
I tested the aquarium water again tonight and got the following reading:
PH 8.2
ammonia 0.25
Nitrite 0
Nitrate 5

I guess I'll keep monitoring to see if anything changes
Rinsing the filter media in tank water, even vigorously, won't remove the bacteria. It secretes a 'sticky substance' that attaches it to objects pretty firmly. To remove the bacteria you'd have to scrub it, much like the flat green algae that adheres to the sides of many tanks. You're numbers are looking good. I doubt that you are suddenly getting "false positive" ammonia readings since you weren't initially, unless your ammonia test solution was contaminated, overheated or frozen, or your test tubes contain residue, causing the appearance of greenish discoloration or that is reacting with the ammonia test solution. You could try scrubbing out a test tube with dish soap and water, rinse thoroughly with distilled water and retest. That might eliminate that possibility.
 

86 ssinit

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Well I’m just going with all the ammonia tests being .25 even the tap water. This has been happening a lot with the api test kits. I guess the last thing to do is test a bottle of water. Shouldn’t be any ammonia in there. Again .25 ammonia is nothing to worry about.
 
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Lauryn

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Momgoose56 said:
Rinsing the filter media in tank water, even vigorously, won't remove the bacteria. It secretes a 'sticky substance' that attaches it to objects pretty firmly. To remove the bacteria you'd have to scrub it, much like the flat green algae that adheres to the sides of many tanks. You're numbers are looking good. I doubt that you are suddenly getting "false positive" ammonia readings since you weren't initially, unless your ammonia test solution was contaminated, overheated or frozen, or your test tubes contain residue, causing the appearance of greenish discoloration or that is reacting with the ammonia test solution. You could try scrubbing out a test tube with dish soap and water, rinse thoroughly with distilled water and retest. That might eliminate that possibility.
Hanging my head in shame......... I have only washed the test tubes with water, I have never washed with a cleaning product. Feels like such a rookie mistake ‍♀
 

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GuppyDazzle said:
Add your readings for ammonia and nitrites, and keep the number at 1 ppm or below.
With a pH of 8.2 that total ammonia reading better be well below 1 ppm. At that pH the danger point is about 0.26 ppm total ammonia.
 

Momgoose56

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Lauryn said:
Hanging my head in shame......... I have only washed the test tubes with water, I have never washed with a cleaning product. Feels like such a rookie mistake ‍♀
Most people never wash them.
 

jdhef

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Lauryn said:
Hanging my head in shame......... I have only washed the test tubes with water, I have never washed with a cleaning product. Feels like such a rookie mistake ‍♀
Hey, don't feel bad, we all make mistakes.
 

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I only rinse my test tubes and caps out with tap water as well. A good rinse out is all that’s really needed. No Dawn necessary imo.
 

mattgirl

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I have a little brush to clean the test tubes. I don't use soap. I just rinse well in very hot water, use the brush and rinse again. I don't dry mine I just put them upside down in my holder. They are dry by the time I need to use them again.

BTW: Your numbers are looking good. Just keep testing every few days until you are confident that they are staying stable. After that weekly water changes should keep everything where it should be.

Test your nitrates before and after the water change. By doing this you can get an idea as to how much nitrate is being produced each week. That number will give you an idea as to how much water needs to be changed each week to keep them from going too high before the next water change.

Unlike medications or any of the many other products being added to tanks, "less is best" but when it comes to how much water to change and how often to do it "more is better".
 
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