Nitrite Spike In Tank Following Water Change

[StatMan]

I had a 240L tank which had been fully cycled and testing fine (0 Ammonia, 0 Nitrite) for a couple of weeks though Nitrates were showing fairly high (80ppm), and had a few fish in plus some plastic plants.

Time came to Plant out the tank with real plants so the following was done:

Removed the fish to a seperate area
Removed 80% of water
Washed Plants in Sink
Planted tank
Replaced Water with Fresh Water and added Fresh Start
Added a couple of heaters to get water up to orginal levels.
Added Back fish

Between Step 2 - 5 the filter was switched off (approx 3-4 hours)
Steps 5-7 was approx 9 hours

12 hours after step 7 noticed a spike in Nitrite to 2.0 ppm, fish have been removed from the tank. It is now nearly 48 hours later and the readings are still showing ammonia 0.5ppm Nitrite 1-2 ppm.

Questions:

Why did this happen our tap water show 0 nitirite?
How do I get the tank bank to a level where it can accept fish? Obviously I currently have other tanks housing fish that should be in this one!
Should I be adding ammonia now the fish are out to help maintain bacteria?


Please note for those reading the Black Neon Tetra thread, it was not in this tank! Just not having a good week!

Appreciate any advice

StatMan

 

[Athena]

Hi - It's not really necessary to move your fish out of their tank just because you have a nitrite or ammonia spike - all you need do is another water change, wait a couple of hours and test the water again. Keep doing that until you get a zero reading.

If you keep moving fish from one tank to the next they will get stressed and become ill - probably quicker than if they were left in a tank with a small reading of chemicals.

So your filter was left off for about 9 hours? Would have been better to leave it running, although I'm not sure exactly what percentage of bacteria could have died off during that time.

Athena

 

[StatMan]

Hi - It's not really necessary to move your fish out of their tank just because you have a nitrite or ammonia spike - all you need do is another water change, wait a couple of hours and test the water again. Keep doing that until you get a zero reading.

If you keep moving fish from one tank to the next they will get stressed and become ill - probably quicker than if they were left in a tank with a small reading of chemicals.

So your filter was left off for about 9 hours? Would have been better to leave it running, although I'm not sure exactly what percentage of bacteria could have died off during that time.

Athena

Filter was only off for 3-4 hours, fish were out for 12-13 hours

StatMan

 

[StatMan]

So the levels have fallen back to near zero 0 - 0.25 ammonia, 0.25- 0.5 nitrite. So I decided to add a few fish back in, Rasboras, within 5 minutes they were all at the surface which was not their normal behvaiour before the water change. and was the situation when I pulled the fish out as they were all regularly going to the surface, which would suggest a lack of oxygen?

Anyway I have done a 50% water change tonight, still don't under stand why a major water change would make this much difference, approx 200L was taken out and I added 40ml of Interpet Fresh start.

Any ideas I am struggling to understand why this happened and how I get back to the stability before hand, didn;t think that putting in new water would have this much difference.

StatMan

 

[destinyxrose]

I'm assuming you don't use an under gravel filter right? That's the only reason I could see it shooting up like that. Maybe using a gravel vacuum could help if you don't use one already. The only advice I have is to maybe bring your water down to a pet store/Fish store and check your stats there. Make sure all the chlorine/chloramines are out of the water and that the temperature of the tank they are in now is the same as their other tank.

As for future water changes, leave the fish in the tank and try to do more frequent changes with less water percentage removal. For instance depending on stats, 30% water changes 2 times a week, or if the stats are high a couple more times a week. Moving the fish back and fourth will stress them out and leaving them in the tank will take away most if not all the shock of the water change.

Hope things get better. Good Luck