# Nitrites in Plant Filtered Tank



## Tampa-Terry (Nov 27, 2006)

Hey, all!!! I just wanted to say hi to everyone as this is my first post on the forum. 

I'm trying to better understand something that's going on in a plant-filtered Rubbermaid stock tank I've got. I say "plant filtered," but I do use a pond pump with a sponge, too. The plants in this case are floating anacharis and hornwort. I treat/condition my water because the city uses chloramines. I have an NH3 monitor that hangs in the tank. It's never really shown detectable levels of NH3. However, just recently I realized that I had detectable levels of nitrites, ~.25.

Since the Amquel binds toxic ammonia, does the NH4 that is created feed the bacteria that converts NH4-ammonia to nitrite? Is that where my nitrites have come from, even though I never had any NH3 to speak of?

The other causal possibility is that I left a Diatomagic filter sitting on the side of the tank (with all the gunk it had collected). That may have been the cause of the nitrite spike I got.

I added salt at the recommended values and did my water changes, and nitrites are just about back where they're supposed to be. I'm continuing to test twice daily and doing water change as/if needed.

I've got Diane's book on order and am just looking for any input or insight on the subject that I can get until I can dig into the book.


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## DataGuru (Mar 11, 2005)

> Since the Amquel binds toxic ammonia, does the NH4 that is created feed the bacteria that converts NH4-ammonia to nitrite?


Yes.



> Is that where my nitrites have come from, even though I never had any NH3 to speak of?


Could be.
How long has the sponge been in the tank?



> The other causal possibility is that I left a Diatomagic filter sitting on the side of the tank (with all the gunk it had collected). That may have been the cause of the nitrite spike I got.


The bacteria that eat debris, do generate ammonia, so yea, that could have contributed. Also if it got anaerobic, you could have incomplete denitrification happening where nitrAte gets converted back to nitrIte.


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## Satirica (Feb 13, 2005)

Just out of curiosity, why are you adding salt? That can really do a number on your plants unless they are all brackish water plants.


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## DataGuru (Mar 11, 2005)

Low levels of salt protect against nitrIte poisoning (brown blood disease) because the chloride is preferentially taken up via the gills.


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## dwalstad (Apr 14, 2006)

*NaCl inhibition of nitrite toxicity*

Nitrites can also come from "nitrate respiration" (my book p. 65). Bacteria under anaerobic conditions will start using nitrates instead of oxygen for their respiration. Your decaying filter material (gone anaerobic) could easily have set up conditions for nitrite production.

Please be careful with filter debris that goes anaerobic. It may only take a few hours for the ecosystem in a canister filter or diatom filter to go bad once the water-flow stops. The bacteria and protozoa suffocate, die, and release toxins.

DataGuru was right-on about using the chloride to help alleviate nitrite toxicity. Very good! The amount of salt (NaCl) required to counteract 0.25 ppm nitrite is probably not enough to inhibit plants.

My Calculations:

Salt (NaCl) kills most plants at 0.1%, which is 1,000 ppm (or mg/l).
A level teaspoon of salt weighs about 5,000 mg. If you add a tsp (5,000 mg) to 20 gal (75.8 liters), you'll get 66 mg/l.

It seems to me that 66 ppm NaCl should be much more than needed to counteract 0.25 ppm nitrite.

Moreover, this level is only 0.0066 % salt, much lower than the level that would theoretically harm plants.

I hope that this jives with the amount of salt people are using to counteract nitrite toxicity.


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## DataGuru (Mar 11, 2005)

Many plants can tolerate brackish water according to this site. here's another page where Bonnie Hale reports the results of some tests she ran on mostly pond plants.

From what I've been able to find, the ratio of chloride to nitrIte needed to protect against brown blood disease depends on the species.
Dr. Saint-Erne's book on koi care says that a 6:1 chloride/nitrite ratio is sufficient to prevent toxicity. 
ARG - Aquarium & Pond Info - The use of salt in the freshwater aquarium or pond
says chlorine at 30 times the nitrite levels
IS1390 Brown Blood Disease
says 10 to 1 ratio of chlorine to nitrIte
Nitrite Toxicosis In Freshwater Fish or Brown Blood Disease
20 mg/liter chlorine
a pub from LSU that says 16 to 1 prevents nitrIte uptake in channel catfish.

(hopefully all those links are still valid, I'm pulling this from an old post of mine)

I'm pretty sure it depends on how actively they scavenge chloride from the water via the gills. Some fish get all their chloride from the diet while others pull it from the water actively. So far, I haven't found a list of what species have or don't have chloride cells in their gills.

back when I figured it out .1% salt would protect against up to 61 ppm nitrIte using the 10 to 1 ratio for channel cats. or up to 101 ppm nitrIte using the 6:1 from Saint-Erne's book.

So I think you're right on that smaller amounts in planted tanks would do just fine. Calcium chloride would also provide the same protective effect without the added sodium.


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## Satirica (Feb 13, 2005)

Thanks for the explanation. I've been lucky enough to not need to know what to do about nitrite poisoning.


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## dwalstad (Apr 14, 2006)

Betty,

Thank you so much for posting this information. I did not know how much excess chloride was recommended by fish keepers.

Chloride competes with nitrite for uptake by the gills. An excess of chloride in the water prevents nitrite uptake by the fish.


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## Tampa-Terry (Nov 27, 2006)

Betty, I squeeze-clean the sponge 2 or 3 times a week in water-change water. I tend to do small, frequent water changes while vacuuming up any detritus.

Betty & Diane, I think I have a better handle on things. The information both of you provided was invaluable to me. I was very, very foolish to leave that filter sitting on the side of the tank. One thing's for sure, it won't happen again.

Betty, I loved reading through all the information in the links you provided. That was incredibly helpful and very much appreciated.

A question for the two of you (or anyone else that wants to share their thoughts) ... how well would Amquel-Plus and NovaQuel have worked deactivating/binding/eliminating the nitrites? I spoke with the guy who developed the product, and he told me that the two products removes all nitrogenous byproducts, but that it doesn't prevent the tank from cycling. Have either of you looked at or used those products?


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## DataGuru (Mar 11, 2005)

From what I've read on it, they say it does, however, they don't know how it works and it doesn't change nitrIte readings, so since I know chloride works, and it's cheap that's what I recommend for goldies. Plus Novaqua and Amquel plus both are slimey and contain extra unnecessary stuff I don't want to put in my water. 

When you say NovaQuel is that something new? or a combination of novaqua and amquel?


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## Tampa-Terry (Nov 27, 2006)

Betty, sorry ... NovaQuel was a typo. Late at night my brain suffers from low oxygen levels. (grin) Should have read/typed "NovAqua."

Nitrite levels are back under control. Zero!!!


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## DataGuru (Mar 11, 2005)

Awsome.


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## t2000kw (Jul 29, 2006)

Remember that with some tests (most tests), though Amquel Plus binds the three nitrogen compounds we're concerned about and detoxifies them, the kits will still read these as nitrite/nitrate/ammonia. There are kits that don't do that. The directions give more detail on this. 

I use the stuff to buy some time if I see a small spike but don't have time to do a water change right away.


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