Did a routine water test yesterday and to my surprise NitrItes were showing 0.5 The tank has been cycled for nearly three months and during this time has always read zero NitrIte. My fish are not their usual selves. I did an 80% water change and got NitrItes down to 0.25. this was at 6pm yesterday. This morning I re-tested and they have soared to 1.0 . NitrAtes are 10 and ammonia is zero. What am Igoing to do? Talk about fish being stressed - what about thier owners!
I read somewhere that dissolving oxygen can cause NitrAtes to reverse back into NitrItes, does anyone konw what this means?

Hiya

Sounds like your cycle has stumbled for some reason - has the tank pH changed dramatically? Did the filters fail for a period of time? Is the tank well-oxygenated? Any big temperature swings? Anything rotting under the substrate or inside a hollow ornament? Did you (or someone lese in the house!) overfeed recently? Add any new fish recently, or treat with any medications, even salt?

Nitrites only become problematic over 1.0 - as long as you keep them below this level your fish will be fine. Adding salt to a .2% solution will also help reduce the effects of the nitrites.

It doesn't usually take long for filter bacteria to recover from a stumble - you should see the nitrites going back down within a week, as long as all is well in the tank.

I have not heard of dissolved oxygen turning nitrates back into nitrites (and from a chemistry perspective it doesn't sound very likely, to be honest).

HTH.

Hi There Woodstock! I've recently had a nitrate problem myself. I received excellent help here. Look in Disease/Diagnosis for the thread titled Help! Fish keep sinking to the bottom. There you'll find about 3 pages of threads that will be very informative to you. How often do you vacumn the gravel? I did very big water changes until I got the nitrates under control. There are some very very knowledgeable people here who will help you; I'm new to the site! My tank is now doing pretty good and my fish are so much better!

Keep us posted!

Hi and thanks to you both for replying so quickly.
my oxygen levels are 5mg/l and my PH is 8.5 -we live in a hard water area so its always on the high side. I haven't messed with the temperature but we have had some very hot days (for the UK) which have dropped down to our normal temperate rainy days so yes the temp of the tank has gone up and down a bit.
I do have a hollow ornamament which I intend to replace. I washed it inside with dechlorinated water on my last water change.
Before these NitrItes rose up I did give my filter a rinse (sponges and wheel) with the fish tank's own water . They had gotten a bit slimy. Could this have had an effect? I usually put in a tablespoon of aquarium salt.

How big is your tank and how many fish? I just purchased some aquarium salt yesterday. The instructions were 1 rounded tablespoon for every 5 gallons...

I know if you read my long thread Fish Keep Sinking to the Bottom...you may find lots and lots of answers to your questions there! I was in quite a panic and got lots of help! Easier to send you there than leave a mega long message here!

My tank is 15uk gallons (18 us gallons) Its on the small side for my two small goldfish but as they are getting bigger I am about to buy a 30uk gallon tank.
I have read your thread and got some useful info -thank you. I hope that Rosie is recovering well. One of my fish Goldie seems very on edge, I will post the details on the diagnosis and disease forum.
Cheers/thanks

! Keep me posted!

I have a question about the water you put in the tank. I have been told not to bother aging the water because it has chloramine added to it. What is the best thing to do? I have a 55 gal and I change out about 5 gals every week. I add the bacteria stuff and condioning stuff each time.

wenmill, when you add water conditioner to water, you remove the chlorine and break the chloramine bond. chlorine + ammonia = chloramine. So, you're left with a little ammonia. It probably shouldn't be a problem for you if your tank is cycled, but keep that in mind. You may even want to use Amquel to remove the ammonia.

When chlorinated water is left to sit out overnight, the chlorine rapidly dissapates. This isn't true for water with chloramine. It stays in the water much longer. That's why you shouldn't bother letting water sit out, just use the conditioner.

Thanks for the reply. My levels of amonia and nitrites stay at 0 and so i guess i'm doing okay!

Same for me. I'm pretty sure I have chloramines in my water, so I just use tap water conditioner and that's it. I'm pretty sure that the cycle can easily handle it.

Took everyones' advice did water changes each day to stop NitrItes going over 1.0 and this morning they registered ZERO

I am so pleased, thanks everyone.

Yay! That's just great news! Congrats Woodstock!