Nitrite Levels and Puffer Fish  8/11/04hi
<Hi, Pufferpunk here>
Just recently I have stripped down my tropical tank and made it into marine.  I brought all my equipment of a friend who was selling up. He kept all of the living rock and coral sand living with the fish.  The nitrites went high then went to zero now they are going back up again.  The fish I have are one regal tang one clown one green Chromis and one porcupine puffer. The tank is Rio 125L filters are the standard Rio filter with a 1000lph power head, fitted and an external filter of about 600lph turnover. I also have a SeaClone protein skimmer.  Should I worry about the levels of nitrite being produced because of the fish or will they be ok while my tank finishes its cycle, is there anything I can do to help this situation and the fish along?
<I never suggest cycling a tank with fish in it.  Ammonia & nitrItes are extremely toxic to fish.  Living in toxic water will compromise their immune systems & can cause permanent damage.  Porc puffers especially, are very susceptible to ich, brought on by a lowered immune system.  I highly suggest finding some SW Bio-Spira to finish cycling the tank immediately.  ~PP>.
              cheers Andy.

Rise In NITRITES
Hello all, <Hi Dennis, MacL with you tonight>
Thanks for all the great advice you give to us! <You are very kind> I hope I won't take too much of your time...Anyways, I recently purchased a cool colony of zoos.  The colony was not mounted to a rock so it wasn't stuck to anything stable.  I placed the colony on a piece of my live rock and it seemed to open up fine, etc.
But one of my scarlet hermit crabs crawled around among the polyps and 1/4 of the colony separated from the rest and fell to the floor of my tank.  <Understandable happens to lots of us.>
I placed the fallen colony piece onto a more stable are of the rock.  Most seem fine, but there were a few "dead" looking polyps floating around.  Wasn't sure if they were dead, so I placed those on a rock as well. <Always best to give them a chance.>
Anyways, I then checked my water later that night and I noticed my nitrites have increased to 0.1 ppm.  My tank has been at zero nitrites, zero ammonia, and
10-20 ppm nitrates for the last 2 months (cycling took about 3 weeks prior to that). <Bit high on the nitrates>> Now all of a sudden a nitrite increase.  I tested the water 3 more times over the next 2 days, but my nitrites are still at 0.1.  I tested my pre-mixed saltwater from my LFS and that has zero nitrites. <I'm guessing that your tank is in the midst of a lil mini cycle where the nitrites and nitrates are building up bacteria to handle the influx of food and fish in the tank.>
Could it be that the dead polyps (which I eventually removed) polluted my tank?  But wouldn't the ammonia also increase? <It could have gone up slightly and dropped very quickly.>
Confused...I did a 25% water change, but not sure what I should do from here...I have always fed my system sparingly to avoid polluting the water and change my
water 1-2 times a week (usually 2 gallon change if once/wk and 1 gallon change if twice/wk) Less frequent changes and a bit more water would be my recommendation.>
Any suggestions?  Should I not feed my fish for a couple of days? <It won't hurt them to let them go without or even cut way back on their foods>
Oh yeah...my specs:
System: 28 gallon; power filter w/ filter pads + ceramic balls in one compartment and Chemipure in the second; AquaC Remora Skimmer; 35 lb live rock; Power
Compacts 130 watt total - 4 lamps in 2 dual daylight (6,700K/10,000K) and Dual Actinic (420NM/460NM)<Keep an eye on those ceramic balls.>
Water: always within 81 (night) to 82 (day) range; salinity/SG stable at 1.02375/32.
Livestock: 1" perc clown; 1" royal Gramma; diamond goby to control algae on substrate; 3 scarlet hermits; 1 abalone; a Majano anemone (another issue); 3 growing
mushrooms (tiny hitchhiker, now huge); tiny sand polyps; the zoanthid colony; tiny yellow cucumber, tons of tiny pinkish bristle worms; a few larger white/translucent bristleworms that scare me; tons of tiny featherduster hitchhikers; hitchhiking yellow
sponges. <Sounds like a lovely tank but you've filled it very quickly. Maybe just leave the tank alone without adding another thing for a bit. Good luck and keep in touch, MacL>
Thank you!

Nitrite Spike!
Hi Crew,
<Hi there! Scott F. with you today>
Thanks for the advice last mail on "pods"!
After a good solid 0/0 Ammonia/Nitrite, I have added a Malu anemone to my 240 litre tank.
It is well (possibly over?) filtered, and although it is maybe a bit new (3 months), it has finished cycling, and is fine with the fire shrimp, hermits, Turbos, and the 2 clowns.
Anyway, the LFS was holding the anemone for me in a tank on its own, with two pieces of small LR, while my system settled.
They are good folks, and I asked them to find me one.
They have a monster filtration system, (Star Wars + Frankenstein's Factory  :-)   ) and the folks there are real enthusiasts, so I don't want to believe there was anything bad going on.
However, after adding the Malu (Saturday), I've got a little Nitrite showing (0.1 -0.2), which I am sure is not good for the anemone?
<Not good for any of your tank's inhabitants, really!>
I added the 2 pieces of LR at the same time, could this be causing a mini cycle ( the LR was taken out and bagged for only about 20 minutes before adding, due to the drive home).
My question is, should I remove the anemone to clean (zero Nitrite) conditions until things settle, or will it be less stressful to leave it in-situ, and do some big water changes, say 20% every day...??
Thanks for all the help......
Bob (UK)
<Well, Bob- it's a reasonable assumption that the rock may have been "uncured", or not entirely cured, and could be contributing to a nitrite spike in the system. My instinct is to remove the anemone to better conditions, until the nitrite reading returns to undetectable levels. On the other hand, the stress of moving this animal around repeatedly may be worse...I'd take the risk and embrace a stepped-up water change schedule and careful monitoring of water conditions until things improve. Make sure that your protein skimmer is working hard, and that you are using a good grade of activated carbon or other chemical filtration media. Good luck! Regards, Scott F>

- Nitrite Creep on Addition of Anemone -
Hi Crew,
Thanks for the advice last mail on "pods"!
After a good solid 0/0 Ammonia/Nitrite, I have added a Malu anemone to my 240 litre tank.
It is well (possibly over?) filtered, and although it is maybe a bit new (3 months), it has finished cycling, and is fine with the fire shrimp, hermits, Turbos, and the 2 clowns.
Anyway, the LFS was holding the anemone for me in a tank on its own, with two pieces of small LR, while my system settled.
They are good folks, and I asked them to find me one.
They have a monster filtration system, (Star Wars + Frankenstein's Factory  :-)   ) and the folks there are real enthusiasts, so I don't want to believe there was anything bad going on.
However, after adding the Malu (Saturday), I've got a little Nitrite showing (0.1 -0.2), which I am sure is not good for the anemone?
I added the 2 pieces of LR at the same time, could this be causing a mini cycle ( the LR was taken out and bagged for only about 20 minutes before adding, due to the drive home).
My question is, should I remove the anemone to clean (zero Nitrite) conditions until things settle, or will it be less stressful to leave it in-situ, and do some big water changes, say 20% every day...?? <Hmm... well, think is also possible the anemone is contributing to the ammonia in the tank... water changes would help. Am I given to understand that this tank is just recently cycled? If so, your system is still getting established, and I'd consider either the large water changes or removing the anemone to a separate, fully-cycled tank while the nitrite gets back down to zero... wait a week after the zero and then you're probably set to put the anemone back.>
thanks for all the help......
Bob (UK)
<Cheers, J -- >

- Reappearance of Nitrites -
Hello Crew,
Thank you for your wonderful website.
I have a 58 gallon saltwater tank.  Fish only (yellow tang, coral beauty, maroon clown) and 2 live rocks.  The tank has been running for one year.  For 11 months the Nitrite reading has always been 0.  
On the advice of a local pet store I started using a product, Marine S.A.T, to treat hair algae.  After 3 weeks of treatments, my Nitrite went up to 1.5. <Could be your test kit reagents are old - I'd get a second opinion on the results of the test kit.>
What do you think of this product? <I've never heard of it.>
How do I eliminate the Nitrite? <Larger water changes, and consider perhaps some more live rock.>
What do you think of AMQUEL or other Nitrite reducing products? <Amquel doesn't reduce nitrites, it locks up ammonia. Am not familiar with anything that addresses nitrites directly.>
I appreciate any guidance.  
Thank you
Tina
<Cheers, J -- >

Prolonged Nitrite Cycle?
Hi,
<Hi there! Scott F. with you today!>
I have a 90 gallon tank. An Emperor 400 bio-wheel filter and a Fluval 404 canister filter. A 165 gph power head  for aeration. 220 watt power compact lighting (I leave on for 10 hours a day). A 400 watt heater. And crushed coral for substrate
I have setup this tank in early December with help from my LFS. I used 9 damsels to cycle my tank. Everything seemed to be going well. By early January my ammonia levels were at 0ppm and my nitrites were high (2-5ppm hard to tell with my test kit) nitrates 0 ppm. My damsels at this time were very active and eating well.  Shortly after I had a good amount of green algae in my tank and thought it was a good sign that my cycle may be complete. When I tested again my ammonia was 0 ppm, nitrite 2-5 ppm, and nitrates 40ppm. I brought a sample of water to the LFS and the confirmed my readings and said my tank was still cycling and the nitrites must be on there way down.  They did not recommend me to do a water change.
<I agree I would wait until the nitrite readings are undetectable before executing a water change>
So I waited. In early February I lost 3 fish (heavy breathing, possible white spots). Once again, I brought a water sample to the LFS and I still had the high nitrites (they measured it at 4ppm) no ammonia and my nitrates were 40ppm. They said the cause of death of the fish was stress due to the high nitrites and I should not worry about treating the tank for parasites.
<Well, I'd tend to agree...Unless you see signs of a parasitic illness, there is no need to treat for such a malady>
This morning I lost another 3 damsels.  I noticed that they lost most of their color and their gills were red.  The other fish are sluggish and color is fading.  I did a 25% water change today.  My readings were 0 ammonia, 2-5ppm nitrites ( I need a more accurate kit) and nitrates between still at 40ppm. I have not read another article pertaining to my current problem. It seams to me with all the articles I read that my nitrites should be dropping (almost 2 months since its peak) especially that I have a considerable amount of nitrates (the tank did start out with no nitrates so I am ruling out my tap water).  My water temp is consistently 78°, Sg 1.021. Any help will be appreciated.
Thanks, Jeff
<Well, Jeff- hard for me to be 100% certain what is causing this cycle to take so long to complete. Lingering nitrite levels are a sign of an immature biological "filter". Sounds like something is interrupting the maturation of the system. Are you doing anything which could be killing the beneficial bacteria in the system? Any medications, household chemicals, etc? The symptoms you describe sound like poisoning of some sort- either metabolite (i.e.; chronic ammonia/nitrite) or a toxin, such as a chemical of some sort. Do re-visit your husbandry techniques, equipment function, etc. There is a logical answer for this anomaly. Do some more digging and you will find it! Good luck! Regards, Scott F.>

Nagging Nitrite and Nasty Disease!
Hi there
<Hello. Scott F. with you today>
My problem is this: I have a bicolor angel that does not really want to eat anything except pick at urchins. I have had it for 2 weeks and it developed a hazy eye which returned to normal, but it was constantly scratching on the substrate but without any spots. This morning it is in bad shape as it has spots and sometimes lies on its side.
<Sounds like it could be either Cryptocaryon or Amyloodinium. Both of these require immediate attention and a course of treatment with a proven medication to affect a cure. Amyloodinium is fatal if left untreated, so do diagnose and act quickly. Much is written on identifying and treating these maladies on the WWM site>
The 3 Marley Butterflies have also contracted it but are eating ok. I have started using TetraMedica in the main tank but how often do I use it?
<Not familiar with this product, but I will definitely recommend that you do not dose in the medicate tank! Use a separate container or aquarium for treatment.>
The anemone does not like this medication either, since it is closed ever since.
<Another example why you should not medicate in the display!>
Sorry, no quarantine tank yet, but am getting one.
<Glad to hear that! it will make your hobby much easier!>
Also added Red Sea vitamin supplement to try and boost the angel. On another note, my nitrite never seems to be 0.
<Not good at all! Nitrite should be undetectable in an established tank. This is definitely a potential cause of stress for your fishes, which can lead to vulnerability to disease. Is this tank fully cycled? Do look for a cause and take corrective measures as soon as possible!>
The tank has been running for 8 months with 2 powerheads of which one has a canister type attachment to it, the other one drive the Jebo skimmer and an Aquaclear 300. The tank is 55 gallons, with 1 Brown Tang, 1
Bicolor Angel, 1 common clown, 2 anemone, 1 Dragon Wrasse, 1 indigenous fingerfin, 3 Marley Butterfly, 2 sea apples, sea star< 20cm diameter).
<Wow! That's a lot of bioload for this sized tank. Do consider a larger tank, or giving some of the animals away. Th overcrowding could explain a number of the problems that you've been having...>
Nitrite test is always lightly pink, and sometimes darker.
Can u please reply to this e-mail address
Thanx, Archie
<Well, Archie- I think that the immediate problem is getting the sick fish diagnosed and treated properly. Then, you need to re-examine your stocking level in the tank. It seems fairly apparent that something is out of line here with the bioload. Do a little research and revise this fish population. Also, re-visit your husbandry techniques (water changes, etc.) to get an idea what has caused this constant nitrite reading. With a little homework and prompt action, you could get this tank back to normal soon. Good luck! regards, Scott F>

Nitrites and ich problems
Bob,<IanB here today>
I have a 75 gal. saltwater with 2 tomato clowns, 1butterfly fish, 1 domino, 1 blue damsel and 1other clowns ( Nemo Type).
Problem is the butterfly has ick, it is the only one I see it on. This is the 2nd day into it. We have been treating for 2 days and I removed the carbon media from the Fluval 304. Now the nitrites are rising! <WATER CHANGES are the cure for rising nitrites...dilution is always the solution> What do I do now? We are new at this. I told my wife if we are gonna be successful, we probably need a QT tank.<yes you do>
Thank you for replying,
Craig Cornett<I would move all the fish to Qt for about 2 months and let your main system go fallow...meaning without any fish because ich can live for quite a while without a host. IanB>

Nitrite Issues (1/30/04)
Hi Crew, <Hi. Steve Allen tonight.>
I hope you are well today! <Yes, same to you.> Thanks in advance for taking the time to answer another stupid question from a newbie to the hobby! <the stupid one is the un-asked one that leads to disaster.>
I have had my 25 gallon tank set up now for about five weeks. I added about 8kg of live rock on day one (it had been in the curing tank at the LFS but wasn't completely cured). Within a couple of days both the Ammonia and Nitrite levels were up to around 1ppm. I then went on holiday for a couple of weeks - I figured
it would be easier to be patient if I was out of the country!
When I got home (about three weeks ago) the Ammonia had dropped to zero, but the Nitrite was at 1ppm. Still nothing to worry about... <Zero is the target.> I then added some aragonite substrate and connected up my home-made 15 gallon Miracle Mud sump/refugium and added a clump of Caulerpa prolifera <lighting?>, and kept on taking those readings.  The Nitrite steadily dropped over the next five days to a level of 0.1ppm. And there it has stayed. For the last two weeks it has stayed at exactly 0.1ppm and refuses to budge. I am beginning to wonder if it will ever drop to zero or if something has happened to interrupt the cycle. Is this possible? <Yes, but usually involves adding something that damages the biofilter.>
Everything else seems to be going fine - the Caulerpa is proliferating, and there is a blossoming population of amphipods and some tiny blue starfish. <way cool> I have lots of different types of algae growing in the main tank. The only other residents so far are 6 snails (3 Ceriths and 3 Turbos), who all seem quite happy.
Other readings of note are all pretty much constant at:
Temp: 24C
SG: 1.024
pH: 8.2
Nitrate: 5ppm
No protein skimmer
I have checked my test kit against freshly mixed salt water and it reads zero Nitrite so I'm fairly sure that I'm reading it correctly. <This can indeed be tough sometimes.> I have picked out a Royal Gramma which the LFS is keeping for me, but I'm
wondering whether his new home will ever be fit for him to live in! <Well, you should quarantine it anyway for 4 weeks in a QT. Read about this on WWM.> Is there anything else I can do - I have an ugly algae / snail tank in the living room and my wife's patience is running out! <Be patient, give more time to cycle. It will take time. This small tank is much harder to manage the water quality of.>
I've attached a picture - although more for your interest / amusement than anything else! <Nice start.> Thank you again, Rob <Hope this helps.> 

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

Nitrites
Hello Chaps
<hello>
I have a 40 gallon tank that has been running for about ten days now. It has around ten kilos of live cured rock. My LFS told me that if I did not get an ammonia spike I should be ok to add a couple a fish which I did (two clowns). I was told the rock would hold all the bacteria needed. Everything is fine apart from I have nitrites at 0.1 and nitrates are very high and no ammonia.
<the tank is still cycling it will take about a month for the process to take place. the process is fish eat, there waste becomes ammonia, ammonia then breaks down to nitrite, and the nitrite is converted to nitrate which is the final product.>
I didn't use RO water from the off (I used Kent Detox). I will use RO in the future. I have had algae problems but this seems to be calming down now. Should I do a water change with RO to bring nitrite and nitrate down or should I leave it and see what happens.???
<do a water change you want the nitrites at 0 (they are toxic to fish and inverts) also adding a protein skimmer (if you do not already have one) would help in keeping them low. MikeH>
Thanks ever so...

Nitrite From "Nowhere"
>Hello all:
>>Hello one.
>I did research the FAQs and found a reply from Bob that touched on my topic about nitrite seemingly appearing from out of the blue.  Bob mentioned that periodic nitrite appearances are not uncommon and can result from bacterial wars, or the dying of old bacteria combined with the regeneration of new bacteria.
>>Haven't experienced anything like this myself withOUT a previous trigger, but I suppose it can be.
>I have a 125G FOWLR that has both the wet/dry and protein skimmer in the sump.  The tank has been running for four years, and I am pleased that four of our animals have made it for that same period of time.  I tested for nitrites last night and the reading was between 0.25 ppm and 0.5 ppm.  The nitrite reading is usually zero (as it should be).  The prior weekend, I did my typical two-week 10G water change while also vacuuming the
substrate, as well as rinsing the wet/dry media in the water that I had removed from the tank.
>>Mmm.. sounds like a bit of overkill.  I would not perform both duties at once, but stagger them.  I also have the habit (especially in new systems--not applicable here but good to note) of never vacuuming more than 1/3-1/2 of the substrate at once.
>Is it possible that, by doing both vacuuming and media rinsing at the same time, I destroyed too much bacteria and caused the nitrite spike?
>>Oh yes, QUITE.  I suggest doing a couple of larger water changes (more on the order of 30%-40%) with no vacuuming or media cleaning whatsoever.  This should help.
>Just wondering...I have 2 tangs and 1 Foxface.  I attach both spinach and broccoli to a clip (after steaming both), as they love this stuff.  I just recently tried adding broccoli to give them something different.  Is it possible that the addition of the broccoli was a factor in the nitrite spike?
>>Well, considering it's quite fibrous, it may have really Ummm.. cleaned their guts, if you get my meaning.  The additional subsequent crapping could certainly account for the nitrite spike, but I would expect to see an ammonia spike first.  I strongly suggest offering Nori.
>As always, your wisdom  and advice is appreciated. Thanks, Mitch  
>>Well, my wisdom is subjective (unless we're talking about those last two teeth), and my advice, well.. I hope it's helpful.  Marina

Nitrites in aged mixed saltwater
hi all,
<Howdy>
I mix 40+ gallons of saltwater mix at a time in adedicated Rubbermaid tuffy 44 gallon trash can with a lid.  it has a powerhead in it for circulation, airstones for aeration, and heater to keep it at temperature.  prior to adding the mix, I dechlor(am)ate the water and aerate for 24+ hours.  
<Okay>
after about 2 weeks, the mix shows high levels of nitrites.
<Really?>
I noticed this the hard way by randomly testing for nitrites after a change, finding high levels in the tank, performing a larger change and finding higher levels.  follow up testing shows nitrites starting to accumulate in the mix after about two weeks.  I've added large amounts of carbon to the container, it doesn't seem to help.
luckily, the biological filtration in the main system is good; lots of live rock and a wet/dry filter.  Even the highest levels of nitrites accidentally introduced with the mix water disappeared within 24 hours.  I'm sure it's not good for the life forms in the meantime.
interestingly enough, there's no ammonia present in the mix at any time I've measured it.
<Time to check the source water, your test kit/s... and try mixing different concentrations of the salt mix to see if this renders different concentrations of nitrite... and maybe looking into another brand>
I'm wondering what the cause may be and what I can do about it.  I've tossed a lot of well aged mix water over the last few months as the nitrites keep creeping back.  I clean the equipment well with just tap water (no ammonia or other cleaning agents), but it doesn't seem to help.  I'm resorting to mixing smaller quantities for 1-2 weeks just for my weekly change and disposing of the rest.  it's a terrible waste, though.
is there anything I can do to rid the mix water of the nitrites instead of dumping it?  and what should I look for as a source of contamination?
<See the above... one of these, likely the test kit being faulty... is at play>
  is my protocol of aerating the mix constantly contributing to the problem?  could it be the tap water, and would an RO or RO/DI unit help solve the problem?
<Possibly the latter, but doubtful... your tap should have almost no appreciable nitrite>
any advice would be appreciated.
thanks,
Pete French
<Please do get back with me re your investigations. Bob Fenner>

Re: nitrites in aged mixed saltwater
hi bob,
<Peter>
since speaking with you last, I stopped aerating the mix water, but continued circulation and kept the carbon in the container.  within three days, the nitrites disappeared.  I don't know if this means it just took 1 week worth of carbon treatment to get all the nitrites out, or if the aeration was polluting the water.  
<... bizarre>
I tend towards the latter; the mixing container is in our basement, about 15' away from well established cat boxes, which could be a source of ammonia in the air.
I suppose the ammonia could have led to a nitrifying bacteria population, and I was basically cycling the water mix.  but I never tested any ammonia in the mix, nor nitrates (even after the nitrite level dropped).
<Interesting. I like this hypothesis>
for the record, I did verify the tests with a dry tab test kit as well, the tap water shows no nitrites, and the mix would not show nitrites until at least two weeks has passed.
<I wonder if there is some way to test... distance from the cat boxes... amount of air pushed through respective samples... to see if there is a connection here. Thank you for the input. Bob Fenner>

Re: nitrites in aged mixed saltwater
> <I wonder if there is some way to test... distance from the cat boxes... amount of air pushed through respective samples... to see if there is a connection here. Thank you for the input. Bob Fenner>
I'd like to identify if this is the cause, otherwise I'll be testing nitrites before every water change.
<Or... maybe running a sponge or other biological filter in your new water bucket...>
I could take two 5 gallon buckets of the existing nitrite free mix, put one on another floor of the house well away from any kitty by-products and put the other one near the cat boxes in the basement, aerate them both and test for ammonia and nitrites on a schedule (every couple of days perhaps).  that should be relatively painless to do, especially if I go snag another couple of SeaChem am-alerts to do the hard part of the testing.
<Yes! A worthwhile experiment>
I don't have two identical pumps, so this wouldn't allow us to factor the volume of air being pushed.
<Mmm, I do think this is a key factor>
perhaps it would be better to use the same pump and do the experiment at two different times?  I could then repeat the experiment on samples that show nitrites with a higher volume of air.
<Worth trying... at least twice, while switching the pumps, and little else. Bob Fenner>

Double Trouble (Illness And Nitrite)
Hey Crew well I am completely dumbfounded please help!
<Will try! Scott F. here today>
I have a 220 gallon tank 175 lbs of live rock 175 live sand refugium wet dry system 55 gallon sump Aqua Clear Aquatics Macro Skimmer (Rio 3100 running it) and a Pentair 40 UV.  Well here's the dilemma: This tank was doing just fine; it has been setup for about 1 year. I added one fish at a time. (lime wrasse, harlequin tusk, blue hippo, yellow tang, dog face puffer, pink tail trigger and my latest addition,  Mr. Queen Angel.
<Quite a collection! That's about as many fishes as you'd want in this tank...>
The angel developed what I believe to be a fungus due to the fact he scratched himself raw just above his eyebrow on both sides. He then developed ich and fungus.  I then noticed the trigger coming down with it so on and so forth.
<Yep- ich is highly contagious...You need to take steps to treat all of the fishes and address the presence of the causative parasites in the main tank>
I purchased Maroxy which said it was ok and will not harm biological filtration. Well, it did.
<Yikes...My advice across the board is never to medicate the display tank! A bit late for you now- but it holds true in the future! Treatment should only take place in a dedicated hospital tank or containers of suitable size to hold your fishes>
The next morning 3.0 nitrite, 80 plus nitrates, ammonia 0 ph 8.4  I have quarantined the angel all is well with the other fish,  I have since changed 50 gallons of water and 70 gallons.
<Aggressive moves, but probably warranted under the circumstances>
Nitrite dropped to 2.5 nitrates 60 ammonia still 0 ph 8.4 cycled with Prime- a new product to me. It says it will detoxify the nitrites and nitrates so that your filter can take over.  I can't take the fish out- I only have a 20 gallon qt. The fish are eating again the disease has subsided and my skimmer is producing a milky type of matter in collection cup.
<Possibly colloids from the Prime? I think that this is a situation where you may want to utilize a commercially available nitrifying bacteria product, such as "Cycle" or "Fritz Zyme" to help speed things up>
I was thinking that I should do a 50% change next after a few days. Your thoughts please.
<Well, if the fish have to stay put, I suppose a series of water changes would help. However, you need to do two things: 1) Re-establish the biological filtration that was lost, and 2) Address the presence of the Cryptocaryon parasites in the tank. My advice would to find some large containers (like Rubbermaid trash cans) to house all of the fishes for an extended period of time, and to treat the illness properly. Meanwhile, the display tank should run "fallow", without fishes, for at least a month to help "crash" the parasite population. You will probably need to "feed" the empty tank to help re-establish the nitrifying bacteria population to cycle the tank. It will take patience and a lot of water testing, but you can do it. Otherwise, you can leave the fishes in the tank while it re-cycles, but the ammonia and nitrite might doom the already stressed and ill fishes. Once the tank cycles, you could then engage in the fallow tank routine and attack the illness...It's a matter of priorities. Good luck! Regards, Scott F>

Nitrites too high
07/22/03
Hello to all at WWM,
<Hi Amy, PF here with you today>
Hate to bother you guys again.  But I really need some advice/help.  I just started another 10g tank and I put some "dirty" water out of my established tank in it about 2-3 g.  My new tank has only been set up a week the ammonia hardly spiked then immediately went to zero but my nitrites are way to high.  I have 3 tiger barbs in it I was wondering  can the ammonia part of my cycling go this quickly?  I am doing daily water changes to try to get the nitrites down.  Can I do them twice a day or just do larger changes or will I kill off any good bacteria I've already got started?  Thanks for any help.  Your site has been so helpful.  I refer to it often.
Thanks
Amy
<I'd go with the twice a day changes, you may want to use a sponge filter for a few days in your main display, and then move it over to your 10g to help seed the bacterial colony. Hope this helps, PF>

Nitrites high in new aquarium
Hi. I hope you can help me because no one has been able to. We have a 40 gallon salt water aquarium and it has been set up for about 6 weeks. The only fish that are in there are a Domino Damsel and a Clownfish. For the last 2 to 3 weeks, every time we do a water test the nitrite is very high but the ammonia is zero and nitrates are zero. We have done 3 10% water changes and have gotten water from a local fish store. (We tested that water before putting it into our tank and everything was perfect in their water.) The water is cloudy and we have rapid growth of brown algae. We have wet/dry trickle filter with a protein skimmer. We have tried using a certain sponge that takes out bacteria and have tried charcoal. We would love to add new fish but the water is always like it is now so we can't. We feed the fish flake food (half a flake per fish per day). We were told not to feed them for about 3 days to see if that helped, and we did that too with still no luck. We have had salt water fish years before and have never had this problem. We don't know what else to do and really hope that you can help or direct us to someone that can. We are eager to get the tank going. Thank you for your time.
<Lisa, you don't mention if you have live rock, type and how much substrate, nor lighting. All can affect the chemistry of the water. Also, have you confirmed that your nitrite test is accurate? The skimmer should be getting a few cups of dark skimmate per week, if not it may need cleaning/adjustment. It may be time to try water changes in the 30-50% range waiting 4 or 5 days between changes. You can search WetWebMedia.com for high nitrites/cloudy water to see if you can get some info. BTW, the brown diatoms are pretty normal in a tank this age. Hope this helps, Don>
Sincerely,
Lisa

Fighting nitrite's in QT tank
>Good afternoon crew,
>>Good morning, Alex, Marina here.    
>I've been doing 20% water changes every day to drop my nitrites down to 0, just like I had them when I first set up my QT tank (10 gallon QT). Right now they are at 0.50 ppm and holding, is that ok?
>>NitrItes?  No, that is too high a reading.  I'm assuming you're using a decent quality test kit as well, something like SeaChem, Salifert.
>The rest of my water is doing fine. Also I'm feeding much lighter every day...Maybe it could be that I only had my Skilter cartridge in my main tank for two weeks only instead of 4 so it can establish beneficial bacteria?
>>Yes, without a full complement of nitrifying bacteria, this would be likely.  You'll get better results changing  50%, or better, of the water.
>Right now I only have a Royal Gramma in my QT tank and he's doing great.
>>Good to know, though he may like enough food to fill his belly.  Do some big water changes so you can feed him well.  This is all part and parcel of quarantine, my friend.
>He's only been there for 1 week.  What can I do to get my nitrites down, or should I ride it with 50ppm and do 10% water changes every day until the QT is up???
>>50% and up is what's going to make a significant change in the readings.  While there certainly are fish that will survive just fine, it is taxing on their health, better to give them a boost during these stressful times.  Also, I'll suggest a regular regimen of added nutrition in the form of Selcon.  I hope this helps!  Marina

Nitrites a problem
I started my 110 gallon fish only tank on March 15, 2003.  I started with crushed coral for the substrate, wet/dry filter, pump runs about 600 gph.
<Ok>
I started with 10 damselfish.  One died immediately and three died at weeks 2,3,4.  
<Most likely from the cycle process. See here for more: http://www.wetwebmedia.com/marine/setup/filtration/biological/biofiltr.htm>
(Side note, all of the Four Stripes died, the blue and blue/yellowtail are still going strong??? Does this surprise you???)  
<Not really, blue damsels are very hardy>
Our ammonia dropped on 4/21/03.  Our Nitrites spiked on 4/23/03 and have been at 1.0 ever since.  I called my LFS and they told me to put in some live bacteria.  We added 5 ounces of live bacteria and NOTHING happened.  I called another LFS and they said to do 25% water changes every other day until the Nitrites hit zero.  We have been doing that for a few weeks.  The nitrites have come down every so slightly, but is this just being diluted by the new water?
<How often do you vacuum the substrate? The canister filter? Add these to your weekly (possibly daily for a while) list of things to do. How much do you feed and how often? I would recommend you look into an appropriate skimmer for your tank to help with dissolved organic wastes.>  
My tank is beginning to become a money pit.  
<Does seem to happen pretty quickly eh?>
I don't want much, just a few clowns, a tang, etc.  Is this too much to ask?  
<Not at all. If you stay diligent in your husbandry practices, you will find success.>
Please help.  Someone said for us to add some live rock but we don't really like the look of it and would rather not if we can at all help it.
<Yes, this an a skimmer would be the two things I would suggest next. Most tangs need a constant source of algae to graze on and this may be difficult to provide without live rock. But you can be successful without the live rock if you keep the tank and filters clean. An upstream, inline refugium with a deep sand bed would help as well with nitrite reduction. Check here for more: http://www.wetwebmedia.com/marine/index.htm. Hope this helps, Don>
Thanks for your help. Carol

High Nitrites  3/20/03
Dear WWM Crew:<You got Phil tonight!>
Brace yourselves....this can be a long one.<Getting ready.. brb going to go to the gym and work-out.. then I'll be ready! lol> I am having trouble keeping my nitrites below 0.1ppm.  A little bit of history...In Dec 2002 I had a half inch of crushed coral substrate which I removed from my 110 fish only tank. I added approx 5" of sand from Carib-Sea. (various grades). I also removed the coral rock I had and replaced with about 45lbs of Tonga branch. The tank is really looking good!<Kool!>  In Jan 2003, I removed the two Aquaclear 500 filters and replaced with a wet dry filter (30x16x18).  The first 2/3 of the filter contains bio balls in addition to the two Cellpore blocks I removed from the AquaClears. I also keep Polyfilter and Chemipure in there. Additionally, I am still running a CPR BakPak skimmer,<Way too small for this sized tank!> a 15w UV,  and a Lifeguard 300 fluidized bed filter. Back in Dec my nitrates where at 40ppm and now they are between 15-20ppm...this I am happy about. My weekly maintenance consists of a 12gal water change and rinsing the sponge in the wet dry.<Try doing more like 20 gallons a week.> However, since I have done some major work on the tank I have been monitoring my nitrites at least weekly. Sometimes the reading is 0.1 and sometimes 0.4. I am using a FasTest kit.<May wanna try a different brand of test kit to check the first one out with.> I was wondering if I am jumping ahead too much and not giving the tank a chance to "settle down" It's only been a couple of months and maybe the tank is going through some additional cycling.<With this bio-load, time is needed.> The inhabitants are as follows (most have been in the tank for almost 2 yrs) and all seem fine:
crosshatch triggerfish 7"
Volitans lionfish 7"
blue streak cleaner wrasse2"
passer angelfish 5"
hippo tang 5"
yellow tang 5"
Cuban hogfish 5"
blue spotted Toby 2"
In Dec I had removed a 11" Vlamingi tang to larger quarters so I actually reduced the bio load.<Your still going to need a bigger tank!> Between the fluidized bed and bio balls I would think I have plenty biological filter surface area. I was actually thinking of eventually removing the fluidized bed. So, the bottom line is should I just watch my feeding and give it time for my nitrites to go down and should I be concerned if I get a reading of 0.1ppm? By the way, the test kit does not have a reading of 0.1ppm. The lowest reading is 0.2ppm. I am assuming since the water is slightly pink when I look through it by the window there is some nitrite. Can nitrite actually be completely zero in a fish only tank do to the constant nitrification process? Just a thought. (FYI my reef tank has zero nitrite....low fish load.)<It all depends on water changes and filtration... See comments above.  These can help you start your way to a nitrite free future... :)  >
Thanks for your valuable time and patience,<No problem!!  Hope this helps!  Phil>

Nitrite Spike?
Hi I have been reading your FAQ's and I wanted to know about the nitrite levels. I have a 5 gal tank set up
<<Way too small... RMF>>
 now for 1 mon, and I have an Angler fish that I have had in the tank. I took my nitrite test tonight and it was reading 0.08 this is the highest it has been. My ammonia and nitrate is 0 the ph is 7.8.
<The pH is a bit low, but within the acceptable range>
I had an orange starfish in there which ended up disintegrating. I ended up tossing it in the garbage, could this be the reason my nitrite level went up so high?
<Quite possible, but I'd expect the ammonia level would be detectable first>
I have about 9 small blue legged hermit crabs and 4 snails in the tank, I took the Angler out and put it in my 20gal tank, as that one is doing good. Everything in that tank reads 0 and the nitrite is 0.01 ph is 8.0.
<Nitrite should be undetectable in an established tank...do re-check>
I did put 2 bigger hermit crabs in the 5gal to clean it up some. could you please tell me if I did the right thing with taking the Angler out and putting it in the other tank.
<I certainly agree that moving the fish to a tank with a (hopefully undetectable?) nitrite level is the wise move. I would have done the same thing>
I did a 50% water change the nitrite reading after that was 0.06.  Your help would be appreciated. Thank you. Margaret.
<Well, Margaret, a detectable nitrite level in an established tank is definitely a sign of either a pollution-inducing event (such as the death of an animal, as you indicated), some kind of major nitrogen cycle disruption, or an indicator that the tank has not fully cycled yet. At this point, I'd leave the tank alone, and not execute any more water changes. Let the tank "re-cycle" (for want of a better term), and monitor the nitrite and ammonia levels regularly. Within a week or two, I'll bet that they return to undetectable levels.  Stay on top of things! Regards, Scott F>

Nitrites
Hi Sir,
Finally I got kits for ammonia and nitrite and I check for it.
Ammonia 0.
<This is good>
Nitrite says less than 0.3 but how much I don't know.
<Any nitrite is not good Shahrukh. This is poisonous to fish, perform water changes to reduce this as much as possible.>
ph    7.5 Temp   22C
But my one fish is lazy and not swimming as he used to be is it because of nitrite that is not less than 0.3.
<Almost undoubtedly. Change enough water to reduce this as soon as possible.>
I have not got nitrate testing kit.
<This is not poisonous to fish, but can cause algae, etc. so this will be required testing in the future, reduce also with water changes, regular maintenance. Craig>

More Fish, More Nitrite!
Hi Scott, or Bob.
<Scott F. here for you!>
How are you guys doing, hope you're doing wonderful.
<Yes, I am! Thanks!>
I wrote you a few days ago, and asked you for a few pointers on my clown trigger, and my lion fish. Well, even my tank is 120 gal, I pictured that, in a few years from now, it will be like me and my wife living in the kitchen for the rest of our lives
<Very good analogy...And, as rooms go- definitely my first choice to be stuck in!>
(so we decided to get a 75 gal for the lion fish only with some live rock and put that aquarium in our office.
<Good idea...you and the fish will appreciate the space, believe me>
But now the problem is that we fell in love with a puffer 4" (Arothron manilensis), and we bought it. Now we have 3 fishes that are doing well in the 120gal tank, but just for about 3 months till the other tank gets fully cycled and put the lion in the other one.
<Okay>
Now my question: I have bought these specimens because we are fairly new in saltwater keeping, and now these fish are very hardy and can forgive many of my mistakes that I will make (even if not on purpose). But for beautiful and super-hardy, and resistant that they are, BOY ARE THEY MESSY EATERS!!!,
<Yes they are!>
So, is there any chance with these 3 specimens for the NITRITE level to be 0.00?
<Well, with a properly cycled aquarium, the nitrifying bacteria population should "catch up" with the ammonia being produced by these specimens. Unfortunately, nitrite in an aquarium is a sure sign that something is out of whack. Sounds like too many (messy) fishes added to quickly to this aquarium. You need to really slow down a bit.>
Because I think it is almost impossible because the food they eat, and the way they eat.
<Not impossible...simply requires careful feeding, maintenance, and patience...>
If not, I already read the nitrite column on http://www.wetwebmedia.com/no2probfaqs.htm, but I do
water changes ever week like 20%, I do not overfeed, and still the NITRITE level is high.
<Well- a lingering high nitrite level is extremely dangerous for your fishes. I don't usually recommend this, but in this case, you may want to add one of the commercial nitrifying bacteria products to help "kick start" the cycle...As much as I'm a huge fan of regular water changes...it may be worth it to hold off a bit until the nitrite level returns to an undetectable level>
How often do you recommend water changes, and how much ????.
<Once a tank has been established, I like 5% water changes twice weekly>
In the store that I bought all my 3 fishes (Aquatic Warehouse) (great store!!!), they sell the salt water.
Do you recommend doing a massive water change 75% of the water they sell there, or doing water changes by mixing the scientific grade marine salt???
<I'd avoid the massive water changes at this point...observe nitrite levels for a few more days to see if they appear to be declining. You don't want to make a bad situation even worse by taking an impulsive action here. As far as purchasing pre-mixed water is concerned...Sure, you can do that, if it's easier and less expensive for you. But personally, I like to mix my own saltwater with RO/DI water. At least I can assure myself that the water is of consistent quality>
Any advice you can give me would be appreciated.. Thank You..
<Well, my best advice is to stay the course here. The nitrite level should ultimately go down with a little patience. It's too bad that the fish have to go through this, but I think massive water changes will just prolong their exposure to this problem. Also- reexamine your filtration and husbandry techniques...With time, diligent observation, careful action, and most of all, patience-things should work out for you! Hang in there! Regards, Scott F>

Re: Tank maintenance / mystery nitrites
Dear Crew,
I am baffled, I thought I had this tank maintenance thing down pat.  Here's the situation, any light that you can shed on it and advice for the future would be most appreciated.
On Jan. 13 I filled a clean 10 gallon tank with tap water in preparation for doing a 20% water change in my freshwater tank on Jan 23. I prepared the 10 gallon tank by scrubbing it with aquarium salt and rinsing it out well.  I used tap water to rinse off the air stone, heater, and thermometer that went into the bare bottom tank.  The tap water that I used to fill the 10 gallon tank had a pH of 7.5, 0 ammonia, nitrites, and nitrates. I left the lid off for two days so the chlorine and chloramines could dissipate, then I put the lid on.  The water has been aerated and heated to 79 degrees Fahrenheit for 10 days (there is no filter in the tank - didn't think I'd need one). Today, Jan. 24 the pH is 7.8 (not a problem), ammonia and nitrates are 0.  The nitrite measures 0.5 ppm.  I did the test twice in case I made a mistake but I got the same results both times.  I tested the tap water in case something was wrong with my test kit and got 0 nitrites.  Why did the nitrite go up?
<something in the tank may have started a cycle, my guess would be the air stone>
What can I do differently in the future to prevent this?
<I would try again with a brand new air stone and see if you get the same results.>
The nitrites in my 30 gallon tank measure 0.  Am I correct that I should NOT use the water in the 10 gallon tank to do a water change?
<The tank should be able to handle the addition of the nitrites, but just to be safe I would start over.  Try a new air stone, and give the heater and thermometer a good scrub.  Let us know how it turns out, I am curious as well.  Best Regards, Gage>
Thanks,
Judy

Duration of Elevated Nitrite Level?
Happy Holidays!
<And you>
I have a new 150gal marine tank with fish only.  The tank is about 6 weeks old, deploys canister filters and will deploy a protein skimmer (currently in stand-by mode).
<I'd fire that device up>
I have seen the ammonia level rise and then fall to zero.  However, my nitrite level has risen to the maximum color indicator on my test kit (5.0ppm) and has stayed at this level for about 8 days.  I believe my stock is experiencing the effect of the elevated nitrite, and several of my fish have died.
<Ummm, what are livestock doing in this tank now?>
My nitrate level has also been steady at around 20ppm.
I was cautious not to overstock the tank nor overfeed the fish.  I have done no water changes yet.  My protein skimmer is still waiting to be turned on.   
My pH has been steady at ~8.0, temp at 77F, salinity at 1.022.
<... Please read here: http://www.wetwebmedia.com/estbiofiltmar.htm and the linked FAQs pages at top>
Question: when will the nitrite begin to fall?  Is there anything I can do in the interim to remedy the nitrite without disrupting the cycle  (water change, turn-on protein skimmer, add more biological filter media)?  ...or am I just being impatient?
<Please read the sections linked re Nitrates. Bob Fenner>
thanks in advance for any help...
Jeffrey Makiel

Brown-banded bamboo shark and nitrites?
Hello,
I have a 150gal saltwater tank with two 60 gal. charcoal filters and a large protein skimmer. The tank had 2 puffers in it with 8 hermit crabs. All the chemicals were fine until one puffer died and the hermit crabs ate up the dead puffer. Ever since then the ammonia and nitrate have been close to zero, while the nitrites shot up to 4ppm!
<it is very unusual to have a nitrite spike after the tank has cycled regardless of the cause... it is evidence of another/bigger problem. Specifically, the nitrite converting bacteria have been damaged or displaced by other bacteria which may or may not be ammonia converting (sometimes they are simply incidental species that do not participate in mineralization but DO displace more desirable bacteria. My advice here is to add new biological media (to culture more nitrite converters) or kill a small part of your biological filter (replace gravel or filter media) with the same hopes. Water changes too of course>
I am doing a project for class on the brown-banded bamboo shark and I need to get it in 2 days! 
<well... not with nitrites>
50% water changes have not helped, maybe even more is needed. Will the shark be able to handle the nitrites if I got it down to 1-3ppm? Any help would be great. Thank you so much.
<if the nitrite is truly 1-3 ppm it will be fine, <<No mate, no. RMF>> but you do need to be sure of why it exists and how to control it. Best regards, Anthony>

Nitrites
Hi gang! <<Hola! Que Paso?>>
Hope your Saturday night is filled with woo hoo's.<<Si.>>
I've had my 55 gal tank running/cycling with 60 lbs of live rock for 2 months. No spike in ammonia or nitrite has been observed (both at 0). So I set up a quarantine tank and added a Sailfin blenny. Now after a week that 10 gal tank has a nitrite spike of 10 ppm (1.0), a ammonia reading of .25 (I think, crappy test kit) and a nitrate reading of 10 ppm. Does the nitrate go up as the nitrite goes down? Is that how it works? Should I add this water to the main tank once the 10 gal has cycled because the main tank hasn't? thanks for your response!
Justaguy
<<With no inhabitants and cured rock and sand, there is no ammonia or nitrite to test.
The QT is quite the opposite, having the urine and feces of a Sailfin blenny to provide ammonia, which is broken down to nitrate, which then produces nitrate, as you found out. That's the nitrogen cycle. PLEASE do change some of this water right away.
If you put the QT water in the main you will/could infect your main with whatever you are quarantining for. So, no, chuck the change water. If all you are adding is a blenny to start, I wouldn't worry about it. You'll enjoy his antics! Craig>>

Nitrites
Dear Bob and Crew,
<<Hello, JasonC here...>>
I have recently developed a nitrate problem in my fish only tank which has lost me two clownfish and a queen angelfish. <<Oh?>> I also had in that tank a cowry which was saved and is unaffected. <<Unusual... it's typically the other way around - fish can deal with pretty high nitrates, invertebrates cannot. Just how high are these nitrates anyway?>>
I probably made the mistake of overfeeding and the fish died. <<That can certainly lead to high nitrates.>>
To reduce ammonia I put new bacteria and made water changes. <<I'm confused now... you've also got ammonia readings?>>
The ammonia decreased, nitrites soared but never came down in 6 weeks. <<I'm sorry, but we seem to be going back and forth here... did something happen that would have destroyed your biological filter? The title of the email says Nitrites [NO2-], you state you have high Nitrates [NO3-], and now you have high NO2- and Ammonia/ium reading as well??? Please elaborate.>>
I decided to remove everything, change the substrate, thoroughly clean the tank and to start again. I did so and after about three days the nitrates soared again and they have been high for the past week. <<I assume you mean NO2-/nitrite?>>
My dealer, who is a reputable one, says he never experienced nitrates to stay in high concentration for more that a week or ten days, but after my last bad experience I am getting worried. <<I suspect you may have a bad test kit here...>>
I probably didn't clean the substrate very well (undergravel filter) before all this happened and I expect that compounded the problem.
Questions:
1- How often and how deeply do I have to Hoover the substrate? How much is too much and how little is too little? <<A little [a section of the gravel 1/4 to 1/2] every water change is probably wise. During the next change, do a different section. How long has this system been set up?>>
2- I wondered whether it is a good idea to change some of it say every 6 months or so. <<Changing won't do you any favors - you have implied here that your undergravel filter is your main source for biological filtration which means that changing out gravel will deplete your biological filter as the new gravel goes through the cycle. This would wreak havoc on your system's inhabitants.>> My dealer says he never changed his and he just Hoovers and his fish are ok. What do you think? <<Changing gravel is usually only necessary to bring in a new source of calcium as existing gravel will slowly turn to dust due to natural processes.>>
3- Is undergravel filter in a fish only set-up really superseded and likely to cause imbalance as it did me? <<Not really... under-gravel filters are still viable technology, although there are newer means of accomplishing the same thing.>>
4 - How do you explain what happened, as my dealer in 25 years experience can't? <<Well, again... I'm curious as to why you have any ammonia readings at all, and I am also uncertain as to which reading is high because you exchanged the words nitrite and nitrate quite often in your email. Likewise, you didn't say what 'high' meant - a number or two would be more meaningful here. Quite honestly, my first inclination is to say you have a bad or old test kit, and would do well by getting hold of a different brand and testing again - look for something specifically for salt water - not mixed fresh and saltwater use. There is nothing really wrong with undergravel filters per se, but live rock is a much better way of building a balanced system. With an undergravel filter, if you are using air-lift only, that could be part of your problem, as the biological filtration needs to be vigorous, and air-lift definitely is not that. You might do well to place some high flow powerheads on the top of the lift tubes and encourage more water to pass though the gravel if this is the case. I would also examine your husbandry here and look for other causes - your question about feeding is in line with this.>>
Thanks
M
<<Cheers, J -- >>

Nitrates (Actually Nitrites)
Dear Bob/Crew,
Just a question about a mishap in my fish-only tank. I used to have a small queen angel and two clown fish in a 70Imp g tank.
I didn't do enough hoovering I think and with some overfeeding the ammonia went up.
<Perhaps too much vacuuming actually... removed or disrupted too much of your nitrifying bacteria>
The fish died alas but a cowry in there was doing ok still. I did water changes and re-seeded the bacterial fauna and waited. Nothing happened. for 6-7 weeks the nitrites were sky high, but the cowry was still ok.
<Cowries can be tough re these insults... but would still like to have your test kit checked.... How high is high?>
I and my dealer were completely taken aback and he said he never seen a tank with nitrites so high for so long in 25 years experience. I decided to take everything out, put the cowry in my other tank, clean it, put new substrate (5-6inches as before, coarse and thin coral sand on top) for my undergravel filter, refill, re-seed and restart. The nitrates went up after three or four days and a week form then they are still at their highest. I am getting a bit worried that history might repeat itself.
<Is the above a mis-spelling? Do you mean nitrites with two "i"s? This is anomalous (not the spelling, but the cycling)... I am still curious re your test kit... would check it against others>
The questions:
1- What happened? What is the longest time nitrites stay high?
<Most often just days to a couple of weeks... at times... in situations where the establishment of biological cycling is interrupted (too much cleaning, a toxic medication use, very heavy overfeeding...) this can go on for a few weeks more.>
The water I started with was ok as nitrite concentration goes.
2- How often and deeply do I have to Hoover the gravel? 
<After the system is going, every week, two weeks... but only "half" and not too thoroughly. Please read here: http://www.wetwebmedia.com/water.htm>
Is undergravel completely useless or too chemically instable even in fish-only systems?
<No... time tested... does work like no other process/technique to establish and maintain biological cycling>
3- Do I have to change some of the substrate at all? My dealer says he only Hoovers his and that it is not necessary.
<I suggest changing out only part of ones substrate after about a year and a half, and then partially every six months or so going forward... to ensure adequate chemical balance. At this point I suggest you add a bit of live rock, look into another test kit, try a tester fish (perhaps a hardy Damselfish) to spur on cycling. Bob Fenner>
Thanks,
M

Re: Nitrates
Dear Bob,
I am always talking about nitrites, not nitrites as per the early stages of the cycle. Nitrates earlier on was a typo.
<Yikes... and even in the subject area>
During the six-seven weeks before I changed over the system I tested it every day almost with a Sera No2 test kit and I went through two.
Nitrites stayed high at 5-16.5 mg/l the highest tone of red on the scale. 
<Wow!>
I spoke then to my dealer who had me take in a sample. We tested and it was the same. Then I decided to take everything out and restart.
So nitrates have now been at their highest for a week. Hopefully they should decrease, don't you think?
<Yes... what is the source of this anomaly? You have no doubt checked your source water, the salt mix... foods alone would not account for this measured concentration. I am wondering if there is a source of nutrient in your system at fault here... Something like a shell (with rotting animal inside), or an "interesting" rock or such item? Do you feed lettuce or other terrestrial greens at all? Some of these have huge concentrations of nitrite (from fertilizer)... worth boiling a bit of water and placing some of these items in it for a few minutes... to test to see if they're the culprit. Otherwise, I would remove all purposeful life, bleach wash the system (recipe for same posted on WetWebMedia.com) and basically start over biologically... to try and discount my only other (major) possibility here... that you have a mix of nitrifying organisms entrenched in your system that won't allow the generation of microbes in succession to convert nitrite to nitrate. Bob Fenner>
Thanks,
M

Re: Nitrates
Dear Bob,
I never fed fish lettuce, only dried algae and Nori.
<Am curious even as to these.>
I have started over biologically. Fingers crossed it should work.
Will be in touch.
<Thank you. Looking forward to your solving this mystery>
P.S. How common is this untrenching of nitrifying bacteria that impairs the cycle? I never heard of it.
<Rare... much less than one hundredth of one percent... but am an old timer (written for the hobby, business, even science of ornamental aquatics for thirty some years... spent fourteen years "on the floor" in retail... helped run a business in this interest for many years... have seen it a handful of times. Odd, but not unknown (not me, well, me and the delayed completion of cycling). Be chatting, Cheers, Bob Fenner>
Cheers,
M

Re: Nitrites
Dear Bob/Crew,
Just to say that my problem with nitrites appears to have sorted itself out. I tested this morning and nitrites are down to tolerable level and, hopefully getting even lower.
Thanks for your prompt responses,
Massimo
<Thank you for the update. Bob Fenner>