Cycle Has Gone Backwards!

[villafan82]

Hi all, i set about re-establishing my old tank you guys kindly helped me cycle as a new aquarium owner a few years ago.
 
Using all the previous advice after 8 weeks of fishless cycling with ammonia i had got to the stage that the aquarium was cycling the 3ppm in 24 hours with 0 nitrites being produced.
 
The issue is:
 
The day after reaching the joyous point I had to go on holiday for a week. So i asked my dad to keep dosing the aquarium with 1.5 ppm of ammonia every few days to keep the bacteria alive.
 
Upon coming back i did my usual checks using api master test kit (PH, Nitrite,nitrate) and all were where you would expect them to be... except ammonia.
 
It is now only dealing with the 3ppm of ammonia in 48 hours, so somehow the cycle has gone backwards.
 
Any advice on what i can do to get it back to the stage to where it is dealing with 3ppm ammonia in 24 hours, and is ready to be stocked?

 

[boshk]

Hi all, i set about re-establishing my old tank you guys kindly helped me cycle as a new aquarium owner a few years ago.
 
Using all the previous advice after 8 weeks of fishless cycling with ammonia i had got to the stage that the aquarium was cycling the 3ppm in 24 hours with 0 nitrites being produced.
 
The issue is:
 
The day after reaching the joyous point I had to go on holiday for a week. So i asked my dad to keep dosing the aquarium with 1.5 ppm of ammonia every few days to keep the bacteria alive.
 
Upon coming back i did my usual checks using api master test kit (PH, Nitrite,nitrate) and all were where you would expect them to be... except ammonia.
 
It is now only dealing with the 3ppm of ammonia in 48 hours, so somehow the cycle has gone backwards.
 
Any advice on what i can do to get it back to the stage to where it is dealing with 3ppm ammonia in 24 hours, and is ready to be stocked?

 
So it goes from 3ppm to 0 ammonia in 48hrs and your Nitrite goes to 0 in 24hrs? Nitrates must be sky high?

 

[Gruntle]

I'd suggest doing as big a water change as you can (siphon the water all the way to the substrate), refill with dechlorinated water and test again. That way, your nitrates will be minimal (and you would have done that before stocking anyway). Test again and let us know what happens.

 

[villafan82]

OK to follow up
 
I just retested. My nitrites are  at 0
 
My nitrates are at 40ppm, which is less than they were before i left and it was ready!
 
Do i do what Gruntle said above and do a say 75% water change , re chlorinate, re-dose with 3ppm ammonia and see what happens?

 

[Far_King]

Nitrates at 40PPM are fine.  I'd suggest a partial water change , de-chlorination of that water before it's added to the tank, dose with ammonia and test again 24 hours later.
 
If the ammonia levels come down and NO3 and NO2 are good then it would sound like you're cycled.

 

[villafan82]

Thanks all.
 
I have just carried out a 50% water change irritating the substrate.
 
Refilled with fresh dechlorinated water.
 
Redosed with 3ppm ammonia and will retest in 24 hours.
 
A quick check of the new nitrate levels shows a drop to 20ppm nitrate down from 40ppm pre water change.
 
Will test ammonia level in 24 hours and update.
 
Thanks for the help so far!

 

[villafan82]

OK Update for you:
 
24 hours after redosing ammonia at 3ppm, following 50% water change.
 
Ammonia 0.25ppm
Nitrite - 0.50ppm
Nitrate - Between 80-160ppm
 
So now the nitirte has gone backwards and is not 0 ppm, within 24 hours...

 

[Far_King]

I'd carry on re-dosing the ammonia for another week.  You can also use flake food to help with the cycle.

 

[Gruntle]

Yes, keep adding ammonia. You shouldn't be far from a complete cycle.

 

[eaglesaquarium]

OK Update for you:
 
24 hours after redosing ammonia at 3ppm, following 50% water change.
 
Ammonia 0.25ppm
Nitrite - 0.50ppm
Nitrate - Between 80-160ppm
 
So now the nitirte has gone backwards and is not 0 ppm, within 24 hours...

 
This is likely the problem.  I'd guess that you have experienced a pH crash as a result of all the ammonia dosed during this time.  The bacteria require carbon.  The nitrate produces nitric acid and will hinder the buffering capability of the water. And if the buffering capacity of the carbonate in the water has been expended, the pH will crash and the bacteria won't be as capable of dealing with ammonia, etc. as before.
 
Do a complete water change and redose again.  Your bacteria will perk up again once you have the carbon (and the buffering capability) in the tank again for the bacteria.

 

[villafan82]

Thanks for the advice all. A few days after the large water change the tank fully cycled.

 

[eaglesaquarium]

Thanks for the advice all. A few days after the large water change the tank fully cycled.

)

 
Cool.  pH crash was the culprit then.

 

[Far_King]

Thanks for the advice all. A few days after the large water change the tank fully cycled.

)

 
Good stuff