Has My Tank Cycled?

[steveb23]

Hi all,

In need of some advice...

I have had 6 fish in my Fluval 90 Litre tank now for just over a month. My fish are 2 guppies, 2 mollies and 2 swordtails.

I started off the tank with Nutrafin Cycle.

I have been testing the water since about 1.5 weeks after putting the fish in, and been doing a 12 litre water change every week. I haven't noticed any of the trademark spikes that I have read you get in the cycle process. I have a low Ammonia count and low Nitrate count, but no Nitrite count at all. Is it possible my tank has cycled?

Thanks for any help!

Steve

 

[KittyKat]

Firstly, most of the "cycle aids" don't actually do anything - just a warning, I do not know about the specific one you used.

And secondly: probably cycled. I would advise against adding any more fish in the next few weeks, but do change to what you plan to have as your normal tank feeding/maintenance routine and keep testing for another week or two.

 

[arobinson1984]

I don't agree that the tanks cycled. If it was cycled, you wouldn't be seeing any ammonia at all.

You said you havent seen any ammonia or nitrite spikes? They would be pretty hard to miss as both last around 1-2 weeks each so if you have been testing quite frequently you would have spotted them, especially as a 12L water change a week wouldn't have been anywhere near enough to keep the levels low so I'd expect them to be sky high.

What exactly are your test results in number? We need to levels in ppm rather than 'low'

Was the filter new? Did you add any mature media from another source?

An important question, does you filter contain either 'zeolite' or any other form of ammonia remover?

Andy

 

[KittyKat]

Sorry, misread. Agreed: ammonia and nitrite must read "0" before it is cycled.

 

[steveb23]

I don't agree that the tanks cycled. If it was cycled, you wouldn't be seeing any ammonia at all.

You said you havent seen any ammonia or nitrite spikes? They would be pretty hard to miss as both last around 1-2 weeks each so if you have been testing quite frequently you would have spotted them, especially as a 12L water change a week wouldn't have been anywhere near enough to keep the levels low so I'd expect them to be sky high.

What exactly are your test results in number? We need to levels in ppm rather than 'low'

Was the filter new? Did you add any mature media from another source?

An important question, does you filter contain either 'zeolite' or any other form of ammonia remover?

Andy

Thanks for your replies.

My results are: Ammonia - I think between 0 and 0.25 ppm
Nitrite: 0
Nitrate: 5 ppm

Filter was new - came with the Fluval 90, and I haven't changed any of the media so I am assuming it doesn't contain an ammonia remover.

Cheers,

Steve

 

[arobinson1984]

Hi Steve,

Do you know which model of filter yours is please?

Andy

 

[steveb23]

Hi Steve,

Do you know which model of filter yours is please?

Andy

Thanks Andy - It is a Fluval U2 Internal Filter.

Steve

 

[fatheadminnow]

What is your tap water nitrate reading? As the 5 ppm of nitrate could be coming form your tap water.

As of right now, your tank is not cycled. A cycled tank will read 0 ppm for ammonia and nitrate and a slowly rising nitrate level. If your tank was cycled, and you have no live plants in your tank, then you should easily have a nitrate reading higher 5 ppm.

Have you been adding a water conditioner to your tank/every time you do a water change? Also, what test kit are you using? As you need to have a liquid test kit as strip test kits are no good and inaccurate.

-FHM

 

[KittyKat]

^^ typo: second line, first "nitrate" should be "nitrite"

 

[steveb23]

What is your tap water nitrate reading? As the 5 ppm of nitrate could be coming form your tap water.

As of right now, your tank is not cycled. A cycled tank will read 0 ppm for ammonia and nitrate and a slowly rising nitrate level. If your tank was cycled, and you have no live plants in your tank, then you should easily have a nitrate reading higher 5 ppm.

Have you been adding a water conditioner to your tank/every time you do a water change? Also, what test kit are you using? As you need to have a liquid test kit as strip test kits are no good and inaccurate.

-FHM

I don't know my tap water nitrate reading - will look into that.


I have lots of live plants in my tank (I think 10) and they all seem healthy.

Am using the Nutrafin Aquaplus water conditioner (is that the same as Cycle??) and using API Liquid test kit although bought the test strips before this and last night compared the two - both in agreement on nitrate and nitrite.

Should also say I have used the liquid kit for all my tests (not the strips!)

Cheers,

Steve

 

[fatheadminnow]

Okay, well the plants will actually use ammonia and nitrate as an extra source of nutrients. So since you are in a fish-in cycle, but are only doing 12 liter weekly water changes and still having a low ammonia level. Either you are starting to colonize some beneficial bacteria but not likely due to the fact you never had a reading in nitrite. So, I would bet that your plants are the key in keeping your ammonia level down.

Also, have you ever replaced anything in your filter?

-FHM

 

[steveb23]

Okay, well the plants will actually use ammonia and nitrate as an extra source of nutrients. So since you are in a fish-in cycle, but are only doing 12 liter weekly water changes and still having a low ammonia level. Either you are starting to colonize some beneficial bacteria but not likely due to the fact you never had a reading in nitrite. So, I would bet that your plants are the key in keeping your ammonia level down.

Also, have you ever replaced anything in your filter?

-FHM

Nope have not touched the filter. Wondering when I should actually...

The only thing I will say which is probably relevant is I was actually away last week on holiday, but I doubt that there would have been any spikes during this time as I would have seen something immediatly before or afterwards?

If its not cycled - I'm at a bit of a loss as to what to do!

Steve

 

[arobinson1984]

I'm guessing its exactly what FHM is getting at.

As you have plenty of live plants in the tank which each consume small amounts of ammonia, they are probably using up any ammonia created by your fish as you only have a few fish in there. If you were to increase the amount of fish in the tank, I'd expect the ammonia levels to start rising.

Andy

 

[fatheadminnow]

Yup^, that would be a logical explanation.

Plants use ammonia, so if you have enough plants in a tank, then that is all you need to eliminate any ammonia.

What we need to know right now is what your tap water Nitrate is? Since nitrate is the end result to the nitrogen cycle, then if your tap water nitrate is 0 ppm, then we would know that you have at least some bacteria within your tank that are processing ammonia to nitrite to nitrate. Since your nitrate reading in your tank is at 5 ppm.

Also, what is the pH and temperature of the water in your tank? A lower pH could be slowing down a present cycle, where as a lower temperature would have the same effect.

-FHM

 

[steveb23]

Yup^, that would be a logical explanation.

Plants use ammonia, so if you have enough plants in a tank, then that is all you need to eliminate any ammonia.

What we need to know right now is what your tap water Nitrate is? Since nitrate is the end result to the nitrogen cycle, then if your tap water nitrate is 0 ppm, then we would know that you have at least some bacteria within your tank that are processing ammonia to nitrite to nitrate. Since your nitrate reading in your tank is at 5 ppm.

Also, what is the pH and temperature of the water in your tank? A lower pH could be slowing down a present cycle, where as a lower temperature would have the same effect.

-FHM

Thanks for that - seems a logical explanation. I'll check my tap water nitrate tonight and come back to you...

My Temperature is 24 degrees C, my PH is unknown as have not tested in a while. Last time I checked it was between 7.5 and 8 which is fairly high?

Steve