Tropical Fish Forum

Tropical Fish Keeping Help and Advice => Fishtank Filtration and Cycling => Topic started by: Dr Um on September 08, 2017, 07:18:03 PM

Title: Stalled cycle? Nitrite repeatedly spiking after addition of ammonia
Post by: Dr Um on September 08, 2017, 07:18:03 PM
Hi,

I'm growing concerned that my fishless cycle may have stalled.  I'm only dosing to 1ppm.  I did a big (practically the whole tank) water change recently.  I originally added SafeStart right back when I first set up the tank, but didn't add any more after the water change, as things seemed to be heading in the right direction.  It seems as though the nitrite-removing bacteria aren't keeping up with the ammonia-eating ones.  Here's the last week-ish of data:

Day 13
30/8/17 - ammonia 0, nitrite 0.25  Then added ammonia -> 1ppm

31/8/17 - ammonia 0, nitrite 2

1/9/17 - ammonia 0, nitrite 0.25

2/9/17 - ammonia 0, nitrite 0  Then did massive water change and redosed to 1ppm

3/9/17 - ammonia 0-0.25, nitrite 1

4/9/17 - ammonia 0, nitrite 0.5

5/9/17 - ammonia 0, nitrite <0.25  Then added ammonia -> 1ppm

6/9/17 - ammonia 0-0.25, nitrite 2 

7/9/17 - ammonia 0, nitrite <0.25  Then added ammonia -> 1ppm

8/9/17 - ammonia 0, nitrite 2

Not sure if I need to do anything or just keep going?  Should I try the 1/3 dose of ammonia as per the fishless cycle guide (wasn't sure whether I should do this, due to only dosing to 1ppm anyway).  Add more SafeStart?

Any advice would be greatly appreciated!  Thanks.
Title: Re: Stalled cycle? Nitrite repeatedly spiking after addition of ammonia
Post by: Sue on September 08, 2017, 07:29:18 PM
Since you have thee Safe Start, I would add some more. it won't harm and it could help.


The nitrite eaters always lag behind the nitrite eaters because they can't start to multiply until the ammonia eaters have made a fair amount of nitrite. And it takes longer for the nitrite eaters to divide than it does for the ammonia eaters.
And once you've added the SS, just keep adding ammonia as before. The good news is that 2 ppm nitrite is significantly lower than 15 ppm, the level which stalls the cycle. It shouldn't take much longer for nitrite to drop to zero 24 hours after adding ammonia.
Title: Re: Stalled cycle? Nitrite repeatedly spiking after addition of ammonia
Post by: Matt on September 08, 2017, 07:46:19 PM
It can take many weeks/months in some cases for a cycle to complete.  Don't get disheartened yet!!  :cheers:
Title: Re: Stalled cycle? Nitrite repeatedly spiking after addition of ammonia
Post by: Andy The Minion on September 08, 2017, 07:50:19 PM
@Dr Um A couple of questions, have you been measuring Nitrate or are the readings zero and you haven't mentioned it? The goal is of course to finally convert the Nitrite into Nitrate, I see your Nitrites are going down so I presume you are achieving this and are getting close to being cycled.
To check if the cycle has stalled measure the pH, it may have dipped and is affecting the bacteria growth. If it is significantly lowered do a water change, just enough to get the pH back up and consider add some Sodium Bicarbonate if you are in a very soft water area to help buffer against a repeat.
Check the Nitrite level after the water change and add ammonia if needed as its level will also have been lowered by the water change.
If this is the problem the cycle should kick back in rapidly and you will probably be back on track in 24 hours.
Title: Re: Stalled cycle? Nitrite repeatedly spiking after addition of ammonia
Post by: Dr Um on September 08, 2017, 08:35:09 PM
Thanks everyone.  I'll add some more SafeStart and see if that speeds things up a bit.  Really want to get on with getting some fish, although obviously need to get the bacteria right first!  I haven't been checking nitrates all that much, although I did check after the water change and they were reading at 40ppm (same as our tap water  - high, I know!).  I think my fishkeeping days are going to consist of endless water changes to keep on top of that!  I haven't checked pH since set-up, but it's normally 7.4-7.6 and quite hard water (15.5 gH) so I would hope a big pH drop would be unlikely.
Title: Re: Stalled cycle? Nitrite repeatedly spiking after addition of ammonia
Post by: Sue on September 08, 2017, 08:45:25 PM
If you tested nitrate just after the water change, it should only have read the same as the tap water you just put in the tank  :) You need to test after nitrite has dropped to see if it has been turned into nitrate.

1 ppm ammonia -> 2.7 ppm nitrite -> 3.7 ppm nitrate.

Assuming your plants do use some of the ammonia you shouldn't see quite 3.7 ppm nitrate for every 1 ppm ammonia that disappears. You may need to wait till two or three 1ppm ammonia additions have been 'eaten' to see any rise in nitrate. With a small increase, it might be easier to tell if you test tap water at the same time and compare the two tubes.
Title: Re: Stalled cycle? Nitrite repeatedly spiking after addition of ammonia
Post by: Littlefish on September 08, 2017, 10:17:55 PM
@Dr Um my tap water nitrates are also 40ppm. I don't find it too much of a problem, and when you stock your tank with fish a few floating plants will help. My tanks that have floating plants have slightly lower nitrate readings than tap water.
Title: Re: Stalled cycle? Nitrite repeatedly spiking after addition of ammonia
Post by: Dr Um on September 09, 2017, 09:05:09 AM
That's really useful about the floating plants - thanks littlefish.  A couple of the fish I'm hoping to stock apparently like these too, so they'll definitely be on my shopping list.

I'll start checking the nitrates again after the next nitrite drop.  I do have some concerns over how I'm going to read the exact level on an ongoing basis, since the difference between the 40ppm and 80ppm colours on the API chart seems absolutely negligible to me!  Perhaps I could dilute the tankwater 1:4 then multiply the obtained result by 5?
Title: Re: Stalled cycle? Nitrite repeatedly spiking after addition of ammonia
Post by: Littlefish on September 09, 2017, 09:11:05 AM
Another thing you can do is test the tap water as well as a "control", and compare your tank water results to the colour of your tap water results. I tend to do this and work on the theory that as long as the colour of the tank results are the same (sometimes lighter with tanks that have floating plants) than the tap water results then it's ok.
Title: Re: Stalled cycle? Nitrite repeatedly spiking after addition of ammonia
Post by: Sue on September 09, 2017, 10:30:03 AM
With the small amount of ammonia you are adding, increases in nitrate will also be small. As Littlefish says, test both tank and tap water at the same time. If the tank tube is slightly redder than the tap tube, that's all you need.