Tropical Fish Keeping - Aquarium fish care and resources

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Elahrairah 06-24-2008 09:10 PM

Nitrite high
I have a problem for about 2 weeks now.

My tank has long been established with no problems. I test Ammonia, Nitrite, Nitrate, Cl, KH, GH, pH two times a week.

Lately I am getting 0.3mg/l Nitirite. 0 Amoinia, 5ppm Nitrate. THis is usual except for the Nitrites, which are always 0. It does not go down no matter what I do. I first noticed it when I saw my neons gasping for air, I put in extra Prime (what the label indicates for Nitrate emergency, I think 10x concentration) and the neons calmed down. I added Biozyme, still no go. I added Cycle. Will not drop.

I use a Magnum 350 and Fluval 304 on my tank (60 gallons) so I think I have enough filtration. I can add another 304 I have if needed (just needs some new tubing). But I don't think that can be the case.

Can the biofilters die off even if you don't touch the filter? What I mean is I only change out the first chamber (filter floss) every 8 weeks or so and rinse the prefilter foams out at the same time in dirty water. I am very careful not to hurt the filters, but can they die off on thier own? I don't touch the ceramic noodles, when I open the filter, first thing I do is transfer them to another container of siphoned tank water. They are out of the filter max 15 min.

I add Melafix, Prime, and Flourish Excel as directed on the labels on each water change (33% weekly). Could any of these be culprits (but I use them all the time)

The fish seem happier since adding the Prime, but the Nitrite has not fallen to 0. It was always at 0 before. Nothing has changed (no new water source, no new fish, no extra food, etc)....and I didn't catch any ammonia spike earlier.

After one week, I did 50% water change, immediate test results after = 0.3mg/l Nitrite...

Is there anything that can add Nitrite to water? Even my Nitrates aren't rising...something is terribly wrong I can feel it. No fish have died yet, but had I not noticed the neons gasping that one morning, it could have been very bad.

Thanks for any help you can give.

One last note: I just remembered I had Discus eggs back then....maybe something in that. I added a small amount (about 1/2 recommended dosage) of Maroxy to help prevent fungus on the eggs (they didn't make it). Could this be it?

iamntbatman 06-25-2008 12:45 AM

Have you tested your tap water?

Elahrairah 06-25-2008 08:43 AM

Yes, forgot to mention.

I use 80% RO water and 20% tap. Both test good.

1077 06-25-2008 09:43 AM

What is your PH what type of test kit are you using? have there been any new fish added lately? nitrification almost stops at PH of 5 or less. Why do you need RO water? some type of buffer is normally used with it . You also have what I would call a soup of different chemicals in your tank. Biozyme, Cycle, Melafix, Flourish excel, Maroxy. The combination may be helping to destroy biological bed. You also may have inadvertantly cleaned filter material too well. I would be interested in water parameters before you put the 80 20 mix of RO /tapwater into the aquarium. do you vaccum the bottom of the tank during waterchanges? Has tank sat over a period of time wth no fish in it? You may have missed an ammonia spike .

Elahrairah 06-25-2008 11:31 PM


Good questions: Let me answer. I use API and Tetra liquid test kits, no new fish in a long time. No period of inactivity.

All weekly water changes of 33% are by vacuuming the bottom (carefully as I have a lot of plants).

Yes, I may have over cleaned my filter, but that would be odd as my procedure is very straightforward and didn't change. Why now?

I use RO water because the nitrates and GH are VERY high in my tap. Nitrates = 35 ppm and GH is over 300 ppm.

KH of my 80/20 mixture is about 4dH so I think it is OK

pH of my tank is a very stable 7.0-7.2 So stable I don't like it, I would like to lower it a bit, but I don't want to do it by adding pH Down or anything like I just live with it that way.

I test all conditions twice a week and never saw an ammonia I test ammonia and Nitrite twice a day, still 0 Ammonia, but 0.3 Nitrite. IT WILL NOT GO DOWN....

Yes, my cocktail is bad, but only the Melafix, Excel and Prime are usual additions. And I have used them for a very long time. The maroxy was because of the eggs (first time using it) and the cycle and biozyme is added only as an emergency fix once I noticed the high nitrites, not before. I wouldn't have used them in any other case (surprised I had them on hand actually). I panicked and didn't know what else to do. I was about to lose 20 neons.

I am starting to blame the maroxy. I know to use the Methylene blue to prevent fungus on eggs, but when I noticed the eggs, my LFS was closed and I had to go to Petsmart and that is all they had. I didn't want to wait overnight. Perhaps I should have.

Next water change I do will be 50% and if I see a decrease in Nitrite, I will know my answer...that will be this Sat. I will post results.

iamntbatman 06-26-2008 12:40 AM

I'm just wondering: why are you regularly dosing with Melafix? It's worked great for fin rot for me before, but I don't know why you'd use it as a regular supplement to your water.

1077 06-26-2008 12:55 AM

It might be possible that combination of melafix and maroxy helped depleat some of the biological bacteria needed and maybe it was further depleated by cleaning the filter ? I have had little expierience with chemicals so I am only speculating but perhaps someone with more knowledge on the effects of these chemicals can weigh in. I do believe that 50 percent water change minus any other additives is a good start. Good Luck and do let us know how things shake out. :wink:

Amphitrite 06-26-2008 06:45 AM

I don't know what's happened here either, but my advice to you would be to cut out every chemical except for the water conditioner and do a series of water changes and see if that helps.

Elahrairah 06-26-2008 08:21 PM

Nitrites = 0!!!

No water changes needed (I will still do 50% this week)

To answer about the Melafix. I don't know why really...I started using it when introducing new fish....but I have gotten in the habbit of one capful for every 20 gallons or so of new water/week I add....

I am sure someone told me to do it once long ago and have ever since....

iamntbatman 06-26-2008 09:36 PM

Melafix is great stuff, but as strong as it smells it seems like something too potent to use on a regular basis. I'm not sure if it has a lot of antibacterial properties, but it still seems like it would be doing more harm than good to dose it on a regular basis. I'd save it for its intended purpose: to aid in the healing of injuries caused by infections or other sources of damage.

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