# 4 weeks into the cycle..NH3/NH4=0 but Nitrites are about .8 ?



## Jeffress77 (Mar 15, 2010)

I went ahead and used a cycle with fish for my startup. It has been 4 or 5 weeks now. pH is stabilized at about 6.9-7.0 I have done 3 water changes at 50% each throughout the 4 weeks.

I just did a 50% change two days ago. 


Ammonia levels have always been 0 for the past few weeks and now my nitrite levels have increased to about .8 Should I do a PWC right away or is this normal for the bio. process?


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## trouble93 (Nov 8, 2008)

Jeffress77 said:


> I went ahead and used a cycle with fish for my startup. It has been 4 or 5 weeks now. pH is stabilized at about 6.9-7.0 I have done 3 water changes at 50% each throughout the 4 weeks.
> 
> I just did a 50% change two days ago.
> 
> ...


Back off on the water changes a bit. This will let the natural bio base build. I'm a firm believer in water changes, but on the other hand I'm a fan of hard water cycles for tanks in the early stages. A hard cycle is just add water and let it go(it will take longer this way, but). This will give your tank a strong bacterial base and a stable bio-filter for a over all more healthy system. I hope this helps.


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## NursePlaty (Feb 5, 2010)

trouble93 said:


> Back off on the water changes a bit. This will let the natural bio base build. I'm a firm believer in water changes, but on the other hand I'm a fan of hard water cycles for tanks in the early stages. A hard cycle is just add water and let it go(it will take longer this way, but). This will give your tank a strong bacterial base and a stable bio-filter for a over all more healthy system. I hope this helps.


*I think you are talking about the fishless cycle. To introduce ammonia into the water and just let it go. He said he is cycling with fish. If I'm mistaken I'm sorry.. *bows down to the moderator* 

My response is a little opposite... Because you said your ammonia level was at 0ppm it means your Ammonia-Nitrite biologic converter action is working. But because you have signs of NitrIte, it shows that the Nitrite-Nitrate bacterial conversion activity is NOT yet working. So your cycle isnt complete yet. NitrIte is what people call the invisible killer, even in concentrations as low as 0.25 ppm because it damages the nervous system and organs of the fish. Even lower concentrations over a period of time can cause long term damage. Im all in for the PWC. When I cycled my tank with fish, I did a lot of WC's to keep all toxins low to prevent spikes. Now, all I do is fishless cycles because its less of a hassel and wont harm the fish. For fishless I did 0 water changes and just kept on adding Ammonia everyday to a concentration of 5-7ppm. 

I would suggest the following for cycling with fish.
For a Nitrite level less than 1 ppm, conduct a 10% water change out 
For a level between 1 and 2 ppm, conduct a 25% water change out 
For a level greater than 2 ppm, conduct a 50% water change out *


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## Jeffress77 (Mar 15, 2010)

Thanks for the help!...Water change in the works for tonight when I get done with work... 

I will keep checking the levels... Thanks!


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## Jeffress77 (Mar 15, 2010)

Ok, Nitrites this morning were right .8 ppm
I did a 40% PWC and tested about 30 mins. after the change. It was still holding at .8 ppm

That doesn't seem possible for something like Nitrites... Is this possible?

For something like Nitrites, I would expect the concentration to become lower after 40% of the water was replaced with a 0 ppm R/O:Tap mixture.


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## NursePlaty (Feb 5, 2010)

*I would expect it to be lower too. The concentration of anything should be lowered by near half if you did a 40% water change. Are you using a reliable test kit? Sometimes test strips reveal inaccurate readings. The reading should be .48ppm or rounded to .5ppm with a 40% water change.*


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## Jeffress77 (Mar 15, 2010)

I am using the Tetra Laborette test kit with fairly new reagents. 

The Nitrite concentration did back off a bit by the next day and is closer to .4 now. I will be doing another 40% PWC soon.


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