Having trouble with Nitrite levels - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 17 Old 12-30-2011, 10:00 PM Thread Starter
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Having trouble with Nitrite levels

I'm new to this website so first things first. Hi everyone!

I have a 75 gallon which had been cycled but now the nitrite in the tank is going up quite a bit. The fish I have in the tank are 3 catfish, 7 cardinal tetras, 2 albino bushynose plecos, and 5 juvenile Discus fish. I've been doing daily water changes to try to get the nitrite to go back down but it doesn't seem to be going down at all. I always add the proper amount of water conditioner and aquarium salt when I do the water changes. I've been doing the daily changes for over a week and it doesn't seem like the nitrite is going down at all.

Is there something I am doing wrong? I really don't want my fish to be stressed, which I know they are because of the nitrite, and I want to fix this as fast as I can. Any suggestions would be greatly appreciated.

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post #2 of 17 Old 12-30-2011, 10:30 PM
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First of all, welcome :)

I'm kinda new here myself, and I know sometimes it takes a bit to hear back from the real experts (worth the wait if you can afford the time though)...I'm far from an expert yet, I only know the hard and fast rules, still learning the exceptions and other tricks lol.

It sounds to me like it is cycling again. As far as I know, water changes are the best thing you can do to save the fish from stress. If you have another established tank where you can divide them up for a while till things settle down, that would really help too.

When you say cycled already, it kinda depends on how it was cycled (how much bacteria you were able to grow) and did all that bacteria live (how long did you wait before adding fish etc) Do you know what the ammonia level is? Also curious on what the nitrate level is to see if it's hitting the third stage.

As an example, If I cycled a 75 gallon with just one fish (or ammonia dosing equivalent too it) then added 15 when it was done all at once, I suspect it would do a full cycle, or close to it all over again.
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TrumpetTwinnie (12-31-2011)
post #3 of 17 Old 12-30-2011, 10:44 PM
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Welcome to TFK,

First a few questions what water conditioner are you using? Certain ones like prime can temporarily detoxify nitrites to aid the fish. Second why are you using salt in your tank? Typically in the freshwater side we only use salt to help treat diseases, but long term it could hurt some inhabitants. Also what are the catfish?

First of all its hard to say why you are seeing a spike in nitrites, typically its because of a mini cycle which can be brought on by a large addition of fish to the tank, or something dead and decaying in the tank. If you are indeed dealing with a mini cycle the only option is really to weather it out (or of course remove what ever is decaying) which will probably mean daily water changes until your beneficial bacteria catch up. The good news is mini cycles only usually last a week or two, but it will require your daily attention.

Also it is a far shot but have you tested your tap water? Sometimes you can get seasonal spikes in ammonia, nitrites and nitrates in your tap water.
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TrumpetTwinnie (12-31-2011)
post #4 of 17 Old 12-30-2011, 11:07 PM Thread Starter
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Hey, thanks for taking the time to answer.

I did a fishless cycle when cycling my tank. That means I just added pure ammonia to the water and kept the ammonia readings at around 4 to 6 ppm while it cycled. I tested the water as I did this and watched the different chemicals spike and drop. It took over a month to cycle completely and then I started to add fish a little bit at a time.

The type of conditioner I use is Tetra Aqua Safe Plus. As for the salt, I thought they needed it, thanks for the info on that. I won't add that anymore. The catfish are 2 albino cory catfish and a regular cory catfish. No deaths in this tank yet thankfully.

Here are the levels for my tank at the moment. Note I have not yet done the water change yet today.

Ammonia: Less than .25 ppm (I'm not good at reading these test things)

Nitrite: Between 1.0 and 2.0 ppm

Nitrate: about 5.0 ppm

If you need more info just let me know.
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post #5 of 17 Old 12-31-2011, 01:12 PM
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Well you are defiantly going through a mini cycle, but can't comment on why. Nitrite levels that high can be quiet deadly for fish. As far as I can tell looking through the product description of Tetra Aqua Safe Plus I can't find anything that it will help neutralize the nitrites, you might want to switch over to a conditioner like prime for right now to help with the nitrites, in fact prime actually has a separate dosing level to deal with nitrite spikes. The only other thing I can really think of is your test kit, which one are you using and how old is it?

I guess your just going to have to do daily water changes of 50% until the nitrites subside to keep it safe for your stock.
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TrumpetTwinnie (12-31-2011)
post #6 of 17 Old 12-31-2011, 01:34 PM
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Hi TrumpetTwinnie! Welcome to TFK, we're glad you came here to get help!
I read thru the whole thread and as questions popped into my head, they got asked by the next person. yeah.
Do you know your water's PH? that can make the effects of the cycling harsher... I think the higher the ph, mine is 8.0, the less effected by this process. Someone correct me if I'm wrong.
Also..You have not answered yet what your tap water readings are...? We're assuming you are using a Liquid API test kit as opposed to the test strips. They can be very unreliable as they are affected by humidity and moisture.
My tap water runs Ammonia at .25 right out of the tap, and I also know I have to be very careful in the spring when they do a chlorine dump to clean out the city pipes. You can smell it when you run the taps.
Prime is what I use now too. It is VERY intense, i.e. a cap for 50 gallons so you won't need a big bottle. Yes it smells disgusting that's normal.
Could one of you experts tell me/us... if a normal full cycle with fish takes 6-8 weeks, does a NON fish cycle take less? or is this member right in the middle half way? They mentioned one month has passed.

Keep up with your water changes!! You'll get thru it!!

Every kid, regardless of what they are going through, is ONE caring adult away from being a success story. ~ Josh Shipp, Teen Behavior Expert
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TrumpetTwinnie (12-31-2011)
post #7 of 17 Old 12-31-2011, 03:45 PM
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Gota love byron and all the great information he drops around here, just checked his bacteria article http://www.tropicalfishkeeping.com/f...quarium-74891/ - and this is what I pulled out

The pH has a direct effect on nitrifying bacteria. These bacteria operate at close to 100% effectiveness at a pH of 8.3, and this level of efficiency decreases as the pH lowers. At pH 7.0 efficiency is only 50%, at 6.5 only 30%, and at 6.0 only 10%. Below 6.0 the bacteria enter a state of dormancy and cease functioning. [5] Fortunately, in acidic water (pH below 7.0) ammonia automatically ionizes into ammonium which is basically harmless. And since nitrite will not be produced when the ammonia-oxidizing bacteria are in “hibernation,” this decrease in their effectiveness poses no immediate danger to the fish and other life forms.
I couldn't find it in his article but I have heard in the past that kept at the top of the optimal range (86F) the bacteria will multiply faster, so in essence a fishless cycle can be quicker if you raise the temp up beyond what you would normally keep most fish.
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post #8 of 17 Old 12-31-2011, 04:30 PM
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Smile try reverse osmosis water...no salt

My Discus eggs just hatched and some are still hatching. I use r/o water...ph 6. No other chemicals, just water changes. They like clean water. Too many water changes and the good bacteria doesn't get a chance to grow. I am not an expert do what you want with my information.
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TrumpetTwinnie (12-31-2011)
post #9 of 17 Old 12-31-2011, 05:21 PM Thread Starter
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Thank you, everyone!

I will take your advice and switch to Prime conditioner, it sounds better than the kind I use. The PH of my water is around 7.6 and my tap water has no traces of ammonia, nitrite, or nitrate in it. I am using the API liquid testing kit, which is a pain to compare the colors to the chart IMO.
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post #10 of 17 Old 12-31-2011, 05:48 PM
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Here comes another question. Do you have any live plants in this tank?

While waiting for that... nitrite at 2 if it really was would mean dead or dying fish. So I must first question the test results--your difficulty reading the colours may be the answer--but even at 1 it is serious. Daily water changes may be saving your fish if nitrite is above zero.

I agree to get a bottle of Prime until this is resolved. While it is not guaranteed, Prime should detoxify nitrite for 36-48 hours. You will still see "nitrite" with the API test until the nitrite is gone completely. "Ultimate" water conditioner also does this if you can't find "Prime." Water changes on alternate days using either of these until nitrite is zero.

I also agree on not using salt. Although, ironically, this can help when nitrite is present. I've forgotten how now. But daily water changes with Prime is still better, as the long-term effects of salt on soft water forest fish like you have is another issue.

Last comment on the higher temperature. Presumably for discus you are around 82F, so I wouldn't adjust that. I don't know exactly if the nitrifying bacteria actually multiply faster with higher temperatures; they are more effective, meaning that each bacterium can process more ammonia/nitrite at 86F than it can at 75F, and so forth. But the actual rate of binary division may be the same, I don't know.

Another question, on another matter: the tank pH is 7.6, what is the tap water pH? [Let a glass sit out overnight to test pH in tap water, it might be different.] And do you know the GH and KH (Alkalinity) of the tap water? I might have something after on this, but not for the present as the nitrite/ammonia is the important issue to resolve.


Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]

Last edited by Byron; 12-31-2011 at 05:56 PM.
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