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FAQs on Marine Water Quality involving Nitrites, Control 

Related Articles: Nitrite, Ammonia, Nitrates, Establishing Cycling, BioFiltrationPhosphate, Silicates, Phosphate

Related FAQs: Nitrites 1Nitrites 2Nitrites 3, & FAQs on Nitrite: Importance, Science, Measure, Sources, Chemical Filtrants, Troubleshooting/Fixing & Nitrates, Ammonia, Phosphate, SilicatesChemical Filtrants

Fix your environment... or change theirs... Add, allow conditions and beneficial microbes to become established, resume metabolism...

Part two: Transient NO2; SW; tied in with gravel vacuuming    7/9/14
In the past I have written to you about a small nitrite reading in my mature fish only system. The tank had been running for ten years or so, and I seemed to get a .5 reading.
<Strange... and you've checked the test kit>

I did as you suggested, water change, not feed until reading came down , but surely the next time I checked there would be nitrite.
This has been going on for 6 months or so. I finally stumbled on what may be my issue, could be a coincidence as well. I perform all water checks and tests a few hours following a water change. This is when I would see nitrite. 20 percent change, or 50 percent water change to remove nitrate., it didn't matter I would test positive for nitrite. I then started testing water in between changes. As I do them every 7 to 10 days. So let's say I would test after 3 days post water change.
I would test zero.
My guess is, by siphoning my sugar fine sand, and moving it around through vacuuming, I was disturbing bacteria, and creating a nitrite spike. Is this possible?
<Oh yes>

I always thought it was good to vacuum fine sand, even when it looked not needed.
Is this typical?
<Not greatly unusual>
And if so, should I halt the siphoning, and just rely on power heads to keep debris and detritus off the bottom? Thanks bob,
<My usual suggestion to only do "one side" vacuuming per period... the other half next time>


Seachem Alpha.    7/2/12
Hi, I was wondering how effective Seachem Alpha is?
<Mmm, "does" what it's labeled to do... a greater concentration of their "Prime" product>
My ammonia is zero but I want to add a relatively large fish and I am worried about an ammonia spike. Are there any adverse effects with this product? Regards, Adam.
<Mmm... these sorts of nitrogenous metabolite counters can't be relied upon to continuously neutralize ammonia, nitrite, nitrate... at any dose concentration. See WWM re. Bob Fenner> 

Nitrite goes marching on -- 2/3/10
<Hello Jesse>
Thanks for providing such a great service to myself and my fellow aquarium addicts!
<'Tis a pleasure>
I recently had to QT my entire tank due to an Ich outbreak. I know it could have been prevented and I have slapped myself on the wrist several times for not QTing coral before bringing it in to my system.
Anyways since I had to pull all 5 of my fish out I went out and bought a more appropriately sized 40 gallon breeder for a QT tank as my 20g was no where near enough for a Kole Tang, Foxface, 2 small Clowns and a Dragon Goby (RIP Obi Wan the Goby). So I brought over my filter for my 20g that was running for 2 months prior, and water from my display, which I know does little good but any little bit helps.
I started out doing small 15% water changes to begin the hypo salinity process every 12 hours.
<Mmmm, I would have dropped this immediately were it me doing this treatment, but this treatment would not have been my choice either>
All of this time my nitrites were high (I never paid attention to the numbers but its pretty much always the 2nd or third level in the API Test Strip).
<Ok. What about ammonia?>
After reaching my desired level of salinity I was hoping things would level off but they have not. I am trying to avoid constant water changes because my assumption is that the tank is going through a cycle.
<Water changes are necessary here>
How is this when the media, a Marineland with 2 bio wheels/media chambers, was running for two months and was already well past its cycle?
<Hmmm, this filter came from the 20 you say and not your display? Did this aquarium have fish inside? The bacteria level in/on a filter media will only be capable of nitrification for a certain bioload. I would say you have exceeded this filters capability here. Alternatively something has knocked back the bacteria, could have been the salinity drop, or chlorine if you were using tap water>
I am very concerned about my fish and although they have seemed to have turned a corner and everyone is eating I believe these nitrite levels are still stressing them out.
<yes, although nitrite is not as worrying as ammonia, yet you make no mention of this>
Any suggestions what to do? Do I just wait this out? Put in some live rock? Sand?
<No, at this salinity it will just cause die-off w/ increased ammonia/nitrite>
I have dosed with BioSpira which seemed to have no effect.
<Hmm, did you check the expiry date? Try Hagen's 'cycle'>
Thanks in advance, the life you save may be my precious fish's
<let's hope so!>
Re: 03/02/2010 Nitrite goes marching on
Also on a side note I use RO/DI water for my water changes. The water is premixed for 2-3 days before its used.
<Good practice, it should be heated as well>
<No problem!>

The Simple Approach To Nitrite Reduction!   12/29/05 Hey there, <Hi there! Scott F. here, back from the limitless void> I have wrote to you all about my 75 gallon saltwater tank that was inherited.  It came with about an 18" zebra moray.  Here is my question.  I have a SeaClone skimmer that was cleaning pretty good, a Rena XP2 filter, and about 40-50lbs. of live rock.  Due having my fish (small Clown, juvenile Blue Tang, juvenile Niger, and sm. Dottyback, and Eel) in a small tank while the big one cycled; I put everything in the big once all my chemical levels zeroed.  Now my nitrites are about .25 and everything else is good.  Sorry to ramble...I have been doing about 5 gallon water changes very regularly to help with this, but nothing seems to work.  Any suggestions? Thanks, Rob <Well, Rob, nitrite in any system is indicative of an "immature" or disrupted biological filtration capability. By doing water changes, you may actually be disrupting the very process that you are trying to foster. My solution to your problem is probably this most simple of all...Don't do anything at all! Just let nature complete the cycle. Given time and a little patience on your part, you'll see the nitrites drop to undetectable levels. Best of luck to you! Regards, Scott F.>

A Mysterious Nitrite.. >Greetings WetWeb crew.   >>Greetings Siaty.  Marina here. >My local fish dealership and I are stuck on a problem with my 65 fish only tank.  The tank is about 6 months old, there is only a piece of dead coral, 1 tiny damsel, 1 small maroon clownfish and 1 small yellow tang.  For about 3 months now, the nitrite levels read high (6mg/L).  Everything else reads perfect (0 ammonia, 0 nitrate, pH = 8.2, specific gravity - 1.023, temp = 78), fish are eating well, 10% water change via deionized water once a week.  At fist, my local fish store thought it was my testing method (I used the liquid aquarium test kit) so they gave me the FasTest.   >>Hhmm.. I don't care for FasTest, but two out of two.. >Similar results.  We have also been putting Cycle into the tank at every water change.  Still, no change.  Any thoughts or ideas?  You guys have always been brilliant! >>I question the test kit.  I would suggest trying something Steve Allen here has been raving about, something called "Bio-Spira", too.  Now, if THAT stuff doesn't do the trick, then I still suspect the test kit.  It's hard to understand why you'd get zero ammonia readings, and even those low nitrate readings are puzzling with only a 10% change/week.  I suggest seeding with the Bio-Spira, test and see what happens.  Oh yes, when you do water changes, do NOT gravel vacuum.  Leave it for at least a month, just change the water, and see what happens. >Thanks a bunch!  Siaty >>You're welcome.  Marina
Addendum to Mysterious Nitrite
>Oops, sorry, I forgot to mention that my tank is filtered by a wet-dry unit with protein skimmer and also an Eheim 2217. >>Well heck!  How come you're getting zero nitrate readings?  According to conventional wisdom, your nitrate should be through the roof!  (J/K, but it doesn't jive)  Marina

Continuing Nitrites... hey bob, I have a very established tank (1 year), that has 2 Fluval 403's, an AMiracle counter current protein skimmer, and a U.V sterilizer, about 50 lbs of live rock, and crushed coral for substrate...I have never had my nitrites at 0... <Trouble... either bad test kit (wish), or continuous die-off of live rock...> I had a bubble tip anemone that died after 1 month, which I heard that anemones have a low tolerance to nitrites (is this true?)... <Most species, yes.> I do a 5 gallon water change about every 1 1/2 weeks...what could I do to get the nitrites to 0?... <Actually no... source is continuous... so dilution will not work... need to figure out source of problem to get to real solution... more bio-filtration will/would help... something like a fluidized bed filter, porous media with water flow over it... like adding biomedia to your canister filters or outside hang on... You should check, increase circulation, maybe aeration around and through your live rock... maybe some powerheads in back, aimed at...> anything I could put in the Fluvals?... <Yes, Bio-Mech, Siporax would be my choices.> I've also recently put a Knop calcium reactor to work on this tank, which after a month has my calcium at a steady 450, and good ph & dKH levels, so far I'm happy with it (just thought I'd tell you)...will the nutrients from the calcium reactor make the water conditions any better for an anemone?...thanks again...Jeff >> <Yes, the calcium reactor is a huge leap in the right direction... do add the particular media listed to your Fluvals> Bob Fenner

Nitrites I have a 50 gallon tank with a built-in wet-dry system. It has been running continuously since 11/98, but I periodically have a nitrite reading--it fluctuates between 0 and .2. This is a fish only tank and contains only three fish--a royal Gramma, a flame Hawkfish, and a Lamarck angel. I change around 10 gallons of water every two weeks. What could be causing the periodic fluctuations of nitrite (pH, ammonia and nitrate readings are invariably good)?  <Perhaps best described as "periodic microbial wars"... with succession, varying populations dying off, being consumed by others...> The tank obviously cycled a long time ago and I have added no new fish in the past 8 months--but my latest water test (yesterday) was .2 nitrite again. I am using a Fastest test kit. Would a stronger powerhead to the built in wet dry help? Linda <More life, more surface area, and yes, more circulation and aeration would make these periodic recycling events more transient, less concentrated. Bob Fenner>

New tank Setup Questions? I was looking through www.WetWebMedia.com and didn't find any suggestions on my problem. <Okay> About 8 weeks ago I began cycling a 60 gallon tank with about 6 damsels. Right now, my ammonia level is zero, my nitrites are at .6 mg/l (have been there for about 2 weeks), and my nitrates are at 0 mg/l. I have a wet/dry and remora aqua c skimmer. Do I have a problem with my setup. There are only 2 fish left in the tank, a damsel and an arc eye Hawkfish (seems to be doing very well - a guy at the pet store told me that he was a very hearty fish and could take a lot of abuse). Any suggestions would be appreciated. Thanks Steve <Likely your system is still cycling, establishing itself... and will be fine. Don't add any more fish or other livestock for now, and be very conservative in your feeding till the nitrites go to zero. Bob Fenner>

Clownfish broodstock tanks Bob, Hope all is going well for you and yours! I was hoping to run a strange question or two past you?  <Let's see how unusual, or bizarre> I'm attempting to cycle my 5th clownfish broodstock system. As clowns will hopefully be spawning in this system I'm limited <limiting> to decor and habitat. Live rock is out of the question as retrieving larvae becomes a back breaking chore!  <Could remove the parents> Live sand only complicates cleaning. As a result of the aforementioned I'm forced to use wet dry filters with bio balls as a primary means of filtration.  <Mmm, wouldn't use such a recirculating system... maybe a gentle overflow (through a fine mesh/netting) to waste... and sponge filters while young are tiny...> The last four systems, which are identical, cycled in about six weeks. This system has been cycling for since the last week in November. I've been using two 5 inch groupers as an ammonia source, and with the system being 200 gallons I have never had any problems in the past. The ammonia portion of the cycle took about a week. Nitrite went way, way, up so I did a massive water change. It was over 60 ppm at one point.  <Wowzah! Unheard of> I was also getting a reading of 100 ppm on Nitrate so I figured a massive water change was warranted. It brought everything down but I'm still getting a nitrite reading of .02 - .05 ppm.  <Should be zip, zero, nada... definitely before stocking> It has been this way for almost 4 weeks. Was the water change necessary?  <Not generally> I read once that after nitrate reaches a certain level it breaks down and becomes nitrite, is this true?  <Mmm, not always... denitrification processes can result in some detectable nitrite under some circumstances> I've never used any chemicals, other then pro-biotic on this system. These groupers have cycled all my tanks and I always take 20 or so bio-balls out of an established tank. I just can't figure it out. Any thoughts are always appreciated. Jeff <Mysterious for sure. Would first check your test kits (the 60 ppm of nitrite is spurious). And would consider rigging up a small lighted sump/refugium with some live rock, perhaps "mud" and macro-algae per culture system... to "soften" and mask these changes. Bob Fenner>

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