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FAQs on Freshwater Quality involving Nitrites: Control

Related Articles: Nitrites in Freshwater Aquariums, Nitrates in Freshwater Aquariums, Biological Filtration, Establishing Cycling, Freshwater Filtration, Know Your Filter Media, A Concise Guide to Your Options by Neale Monks, Setting up a Freshwater Aquarium, Tips for BeginnersWater Quality and Freshwater Aquariums

Related FAQs: Importance, Science, Measure, Sources, Chemical Filtrants, Troubleshooting/Fixing, & Ammonia, FW Nitrates, Freshwater Nutrient Cycling, Establishing Cycling 1,


Testing freshwater tank - 11/22/2012
I just have a quick question.  I have written a few times and appreciate your advise immensely.
<Thank you for these kind words.>
I have a 26 gallon tank I did a successful fishless cycle on but after a large water change and adding fish, I have had reoccurring nitrite problems so I have continued 25 percent water changes for almost 2 months. 
<This is the appropriate course of action.  Good job.  Just as a note, the Nitrite troubles were probably caused by the bacteria load simply building itself up to the fish load.  Not exactly unexpected after a fishless cycle, especially if fish are added faster than the bacteria can grow to compensate.  Water changes were the exactly right course of action.>
The other day I noticed, what several pictures lead me to believe, was fin rot on one of my guppies and so with no hospital tank available, I treated my tank for 5 days with Maracyn 2.
<Good water quality alone is typically enough to "fix" a tiny bit of fin rot....>
I have two Platys, both of which appear to be acting a little more active since the treatment and four male guppies which have always acted fine but the one guppies dorsal fin still looks ragged and white on the tips. My question is, now while testing my water the ammonia and nitrites are both zero. 
<Bacteria load finally catching up, most likely.>
While I am excited, is this new absence of nitrites really real or could the presence of the Maracyn be giving me false readings? 
<Oh!  No, probably not getting a false reading, here.  It's expected that, over the course of time, the bacteria will soon (within weeks) be able to take care of the whole fish load - provided the tank isn't overstocked, of course.>
I use the API master water test kit.  Also, one of my Platys just had fry which I think they have all eaten but periodically has had very, very long stringy white poop and stays near the back bottom of the tank although will swim around some and always comes out to eat.  Could this be internal parasites or is it just constipated? 
<Either, or neither....  Possibly a reaction to the medication, even....  I wouldn't do anything about this just now, though.  Observe, and once you've finished medicating with Maracyn 2, make sure to do a very hefty water change, and continue to test for a while to ensure that the bacteria weren't wiped out by the medication.>
Thanks again for helping this newbie keep her sanity!
<Stay sane!  Or at least partly sane.  No fishkeeper is ever *completely* sane, I think....  *grin*  Happy Thanksgiving!  -Sabrina>

Nitrite problems for my 10 gal sick tank   1/15/10
I have another question on top of the bazillion others I have emailed for...I set up a quarantine/sick tank for a few new fish I received from someone about 10 days ago.
I used tank water from my established 55 gal to put into the 10 gallon so I didn't have to cycle it.
<Water won't cycle anything. There are few filter bacteria in the water column.>
I didn't have time to wait.
<You need to move filter MEDIA from the mature aquarium to the new aquarium, NOT water. A mature filter can lose up to 50% of its biological media without problems, so you can usually "transplant" useful amounts of biological media very easily.>
because of this, I used a small hang on the back penguin filter that was new. new bio wheel, and new carbon filter. now, my problem is, my nitrites are too high...2.0-3.0, ammonia 0, nitrates 1.0. I understand that the water needs to be changed because nitrites are toxic, so I do a water change (50%) using the 55 gal water (ammonia 0, nitrites, 0, nitrates, 2.0) but no matter how much I change out the nitrites still remain 2.0. only when I do a double water change, 50% in the morning and 50% later in the afternoon can I get the nitrites down to 0 but the next day its back up to 2.0. I have a suspicion that it has to do with the new filter not having any good bacteria but I feel that I cant keep changing out the tank water like this. I'm trying not to stress out my new fish but I dont know what else to do. please let me know what I am doing wrong.
<Your mistake was thinking the water was going to help. It won't. Move as much media from a mature filter as you can into the new filter. Assuming water chemistry and temperature are similar in both tanks, the filter media will instantly provide proper water quality. Cheers, Neale.>

Re: nitrite problems for my 10 gal sick tank   1/16/10
ok...that makes sense. how do I go about changing the media?
<Depends on the media. Ceramic noodles and filter floss can just be taken from media compartments in one filter and stuffed into another. Sponges may or may not be amenable to this, depending on their size. A pair of scissors
might be used to cut sponges down to size if required.>
I have a large canister filter on the large 55 gallon but a small hang on the back filter on the small tank?
<This mismatch is one of many reasons why I don't like hang-on-the-back filters. When it comes to donating media, they're dogs to work with, since they so often rely on tailor-made filter modules (like proprietary razor
blades and inkjet cartridges, all designed to lock you into buying from one manufacturer).>
also, I just remembered that I didn't mention that I didn't put any gravel into the small tank so I can make sure to suck up all the debris at the bottom and to make it easier to break down when I can combine the fish.
anyways, what exactly do I do to put media into the 10 gal from the 55 gallon tank? do I cut a piece of the filter pad and stick it into the 10 gal filter?
<Donate about 50% of the media. How will depend on the media type.
Obviously you're donating BIOLOGICAL media, not carbon, Zeolite or any other chemical media (i.e., the stuff you replace monthly).>
<Cheers, Neale.>

Nitrite and Nitrate Problems
Controlling Nitrite and Nitrate Problems  10/15/09

Hello Chuck, I got another question for you concerning the same 30 gallon tank. We for a little while have had a problem with ammonia being really high, so we started doing 50% water changes like every 3 days or so but only vacuum the surface of the gravel so we don't disrupt the biological filter. The good news is the ammonia level is good now however our nitrites and nitrates are off the charts. Question is should we continue to do the water changes to bring these levels down or is there some other way we can bring these levels down to a safe reading? The fish seem to be happy and are very active, we are just concerned about these levels being harmful.
Thanks, John and Anika
< The good news is that the nitrites and nitrates are less toxic than the ammonia. I would watch the amount of food fed each time. Remove any uneaten food after 5 minutes by using a siphon. Clean the filters often
too. Plants will remove some nitrogenous wastes if they are healthy and the lighting is strong. Using Dr Tim's One and Only will help quicken the process. One you are dealing with just nitrat4s then you can try to control them with water changes and try to keep them under 20 ppm.-Chuck>

Freshwater nitrite confusion  - 11/13/06 Hello Crew, <Pam> It's been a while since my last question. Still a novice... I've been doing some reading, and can't seem to find the exact info I need. Most of what I can find deals with salt water tanks and not freshwater. I'm trying to find out how to interpret these test results. <Let's "fill out" the FW nitrite FAQs a bit here> My 10 gal tank has been cycling for about a month now, with 25% water changes weekly  (Well water; no chemical additives typical to a municipal supply. <Mmm, a comment... during cycling (I take it, hope there are no livestock present), such (large) water changes are to be avoided... tend to put off cycling...> Tests safely on all levels prior to adding to tank.)   I only have one 1 1/2 inch long goldie <...> and no live plants. I'm feeding once per day. Current levels in this tank are as follows: Ammonia: 0 ppm Nitrite: 2.0 ppm <Yikes... way too high, toxic> Nitrate: between 10 & 20 ppm Ammonia levels have been consistently dropping, while Nitrite levels are going up, up, up. Do I simply continue the water changes and wait for the nitrite levels to drop? <Mmm... yes, along with very scant feeding... perhaps (advised) the addition of a purposeful adjunct (BioSpira... from Marineland), and/or perhaps some other source of useful bacteria... like the live plant you alluded to> Add some conditioner? <Mmm, the bacterial product above> Vacuum the gravel? <I would not... But would change the water to keep nitrite below 1.0 ppm, not feed anything if it goes over this threshold> I'm stumped... Thank you so much for your time! P. Bass <You have read on WWM re FW Cycling: http://wetwebmedia.com/FWSubWebIndex/fwestcycling.htm and the linked files above? Bob Fenner>

FW nitrite but no nitrate  - 04/07/06 Greetings, <Hello, Karen. Tom> I have a 29 G tall freshwater tank.  It is filtered with a UG system and a powerhead using reverse flow, accompanied by an Aquaclear power filter. I am in day 33 of the tank's cycle. I have 6 Zebra Danios. I have no ammonia, 5 mg/l nitrite <Same as '5 ppm' for those taking notes. And, thank Heaven you've got Danios in your tank! :)>, and 0 ppm nitrate. I have done 4 H20 changes @ 10 gallons each time. These levels have been this way for about a 5 or 6 days. When am I going to get nitrate and, can I hasten this? I don't want to harm the fishes. <Karen, you've got a couple of options. The first is to stop doing the water changes and, the second is to stop doing water changes and add Bio-Spira (Marineland) to your tank. The Nitrosomonas bacteria that convert ammonia to nitrite has established itself. Not so with the Nitrospira bacteria that convert nitrite to nitrate. (Before I'm hanged in effigy by all of you 'Nitrobacter' fans, please see: http://biology.kenyon.edu/Microbial_Biorealm/bacteria/nitrospira/Nitrospira.htm) Your nitrite levels are far from being in short supply for the bacteria to feed on but your water changes are excessive for a "cycling" tank. The Bio-Spira contains the "live" bacteria that would jump-start the conversion. (Please don't waste your money on "off-the-shelf" treatments. Bio-Spira is a refrigerated product and must be kept refrigerated to keep the bacteria viable.)> A second question: regarding a quarantine tank - Is it all right to keep it up and running with just a few Danios in it, then I would remove them to the display tank while I was quarantining new arrivals or medicating any other fish? <Answer: "Yes". Now I'm going to tell why you shouldn't do it. First, handling fish is stressful to the animals. Danios may be tough but they deserve the same treatment that any other fishes deserve. Second, no "quarantine" procedure is perfect. Ideally, the QT should be broken down and thoroughly cleaned after each use. (Yes, you may be conscientious enough to do this but others may, unfortunately, infer differently, i.e. leave the QT running all the time and just keep adding/transferring/medicating fish. Not what we at WWM prescribe at all.) Last, there are "fishless" methods to keep a cycled, unoccupied tank, if you must.> Thanks for your time. If I can help you by answering any questions about computers, whitewater kayaking, breastfeeding, or the meaning of life, feel free to ask. : ) <A rather "eclectic" mix of topics, to be sure! :)> Karen <Tom>

Nitrite Control I currently have 3 long, black finned tetras, 3 Mickey mouse platys and 1 algae eater. I just checked my water a couple days ago and everything is fine except the nitrites and nitrates are high. I put in more of the Stress- Zyme which is supposed to lower it but I checked and it hasn't, is there anything else I can do for it??? Another question, not right now but in a while, I was going to get some more fish (I have a 20 gallon tank, so I was thinking 3 more according to your recommendations). Do you have any good fish that would be compatible with mine. Thanks so much, you guys are the only reason my fish are still alive. Kelsey <Those nitrites need to go away. The cure is a water change. Up to 50% at a time. Make sure you remove the waste and old food by using a gravel vac. Feed lightly. Even skip a day once a week. No more fish until ammonia and nitrite stay at zero for a week without a water change. Then set up a water change schedule that keeps the resulting nitrates below 20ppm. Do as many as needed for now to keep that nitrite at zero and until you establish good bio filtration. No chemicals needed. Please read here. http://www.wetwebmedia.com/FWSubWebIndex/fwestcycling.htm  As to tankmates, a group of three or four Corys would be a great addition. Don>

Nitrite and Ammonia still high after 5 weeks I have a 10 gal freshwater tank set up five weeks ago. Nitrite levels are still .5 and ammonia .25. I do 10 to 20% water change every 4 to 5 days by vacuuming the gravel trying to get those levels to 0. <I would not change the water... unless the ammonia or nitrite approach 1.0 ppm... and feed VERY sparingly in the meanwhile... the water changes are forestalling the establishment of biological filtration...> Nothing seems to help. The water I'm putting in is reverse osmosis water and shows 0 nitrite and ammonia. <Umm, you'd be better off with at least some mineral content (i.e. non-R.O. water) being mixed in here... try taking out a few gallons (w/o gravel vacuuming) and adding some tap water...> My tank currently has only 1 Serpae tetra as all the others have died of ich. I am still treating the tank with CopperSafe until 30 days are up (1 more week). I don't understand why I can't get those levels down. Thanks, Tina <Mmm, Tina, someone/s have not been making known to you more of a/the "full picture"... that is, what you need to know. The Copper is also killing off the beneficial bacteria you need to convert ammonia and nitrite to less noxious products... There are a few things I would do at this point. First and foremost is for you to READ, understand what biological filtration establishment and ich actually are: http://www.wetwebmedia.com/FWSubWebIndex/fwestcycling.htm  and http://www.wetwebmedia.com/FWSubWebIndex/fwich.htm  and the Related materials, linked, in blue, above... I would raise your water temperature to the mid 80's F (this will kill the ich, save your Serpae... and speed up establishment of biological filtration). STOP using the Copper product, all such "medications"... You will soon understand enough of the underlying factual material to be aquarium-confident, proceeding beyond these present troubles. Bob Fenner>

Re: Nitrite and Ammonia still high after 5 weeks Thank you so much for your prompt response. I have read the links you gave me which leads me to more questions. Even though I did a ton of research before I started this tank (which incidentally was a Christmas present for my 8 year old daughter) I seem to have overdone a lot of things.  <Yes> I did let the tank run for 4 days before I added any fish but then I added three cherry barbs right away. <There are ways... as you now know... to "break in" a new system... but this was too much too soon> They seemed really happy so after 4 more days I added 3 Serpae Tetras. That's where things started getting out of control.  <Actually not where, or even when... think about this... all this life produces wastes, which poison themselves... and not enough biological filtration going...> I was having trouble stabilizing the water and kept doing water changes every 2 or 3 days. When the ammonia got high I added "Ammonia Clear" then the next day I would have a bacteria bloom and freak out that my water was cloudy so I would do more water changes. After three weeks the filter was really dirty so I changed the Whisper carbon filter but I did reuse the original framework that goes in the bio bag as they said it would have built up beneficial bacteria. <Yes, good> After all this one morning the male cherry barb looked like he had been sprinkled with salt after identifying this as ich I quickly ran to Petco where they advised me to put CopperSafe in the tank and it would fix everything. It didn't, the other fish rapidly showed signs of ich and they all died a slow agonizing death. It was horrible to watch. (some Christmas present) The only fish that was not affected was the largest Serpae who seems to be immune to ich. He never got a spot. Now that you have the background here are the questions. My husband thinks I should just dump this whole tank and start over since I've messed up so many things trying to give them tender loving care. What do you think? <I would NOT start all over... but you might> The tank has been running at 80 degrees for about 2 weeks. I will turn it up higher like you mentioned. Were you suggesting that I remove all the CopperSafe from the water? <It's gone... absorbed by material in the tank, fallen out of solution> Should I put the carbon filter back in? <Yes> To clarify my previous e-mail I have only put in about 5 gallons of RO water in the tank, the other five were treated tap water. <Oh, good> I have noticed that when I stir up the water in the tank when cleaning hundreds of pieces of what looks like mucus or skin start floating around the tank. Do you know what that would be. Is it from the fish that died, or ich, etc. <Don't know... could be scales, copper flecks...> Last of all I just want to mention that the Tetra looks great very brightly colored and healthy. When I feed him I only put in a few pieces at a time and quickly remove what he doesn't eat. Sorry this was so long but your my only reliable source of information. I can't trust the high school kids at Petco that never had a fish. Thanks, Tina <Take your time... wait a few weeks and see how the tank looks, feed sparingly till there are no nitrogenous waste anomalies... Bob Fenner> 

Re: Nitrite and Ammonia still high after 5 weeks Thanks again Bob.  I will put the carbon back in my filter and raise the temp.  I will slow down on water changes.  Is once a week still too much?<Not as long you don't touch the gravel.  Syphoning the gravel will remove the bacteria that you are trying to produce.>  Would you recommend that going forward I do not always vacuum the gravel with every water change?<NO, once a month should be sufficient.> Should I wait until the water is completely stabilized before adding another Serpae? <Yes, absolutely.> This one seems so lonely since all of his buddies died.  I don't have an isolation tank since this is our first try at tropical fish so I'm nervous about when I do add another fish.  According to one of those links you gave me it sounds like if the conditions are good in your tank there is less of a chance of a fish getting ich. Tina <Tina, let the tetra be in the tank for about 2 weeks after the tank has stabilized.  This will remove the ich from the tank.  Once the water quality is stable then you start your time for the 2 weeks.  Then you add fish 2 or 3 at a time.  I would suggest one addition of fish a week.  This will give your biological filter time to recover from the addition of the new fish.  good luck. MikeB>

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