Nitrite toxicity levels between fresh and saltwater

[kmacc05]

So I was doing some reading and came across this interesting write up on the differences in toxicity levels of nitrite between fresh and saltwater systems.

From their testing, it seems marine and reef habitats aren't nearly as susceptible to nitrite poisoning as a freshwater habitat. They seemed to add nitrite directly to the test water, rather than letting a spike in ammonia happen first to lead to the spike of nitrite. I assume this means that if nitrite rose to a toxic level, then the ammonia would have had to have been higher than toxic way before hand. And if we do our job and keep ammonia undetectable, then nitrite should not be a worry.

Is this correct? What opinion do you all have on this subject? I found it interesting.

http://www.reefkeeping.com/issues/2005-06/rhf/

[Planeden]

They added nitrate and not ammonia so they could isolate the effects of the two. You are probably correct that high nitrites will probably be associated with high ammonia levels in the tank, so the ammonia may be a bigger problem. Although, aside from scientific interest, I'm not sure I see an application in the aquarium. Maybe it is my lack of reef experience, but in a well established tank ammonia and nitrites will remain at zero. If you test and find nitrites it is probably a simptom of a problem that may be caught and corrected early.

[Timfish]

I'd have to agree with Planedon, it's interesting scientificly and improtant for people to understand the nitrification cycle but not much of an issue in reef systems with all the animals that are using ammonia, nitrite and nitrate for food. A drawing in "The Reef Aquarium" pg 255 shows the rather complex nitrification cycle with mineralzation, assimulation and dissimulation processes working concurently. Some of the dissimulation processes are doing the reverse of of the mineralization process and converting nitrates to nitrites then to ammonium so nitrites can also come from the nitrate in a system. It's interesting to note some corals have been shown to use symbiotic cyanobacteria to fix N2, nitrogen gas, into nitrates for use by thier symbiotic dinoflagellates.

A simple experiment I encourage everyone to do to get an idea of what's going on in your aquiarium is to test the ammonia in new RO or RO/DI, then test again when salt is mixed, do a 30% water change and test the DT after one hour and again 1 day later.

[kmacc05]

hmmmm thanks for yall's input.

That is interesting Timfish, would that explain why occasionally I would get small traces of nitrite in my last tank, but never any ammonia? I need to get that book. I have heard a lot of good things about it. Seems to be the "Bible" for the hobby.

[Planeden]

I'd have to agree with Planedon, it's interesting scientificly and improtant for people to understand the nitrification cycle but not much of an issue in reef systems with all the animals that are using ammonia, nitrite and nitrate for food. A drawing in "The Reef Aquarium" pg 255 shows the rather complex nitrification cycle with mineralzation, assimulation and dissimulation processes working concurently. Some of the dissimulation processes are doing the reverse of of the mineralization process and converting nitrates to nitrites then to ammonium so nitrites can also come from the nitrate in a system. It's interesting to note some corals have been shown to use symbiotic cyanobacteria to fix N2, nitrogen gas, into nitrates for use by thier symbiotic dinoflagellates.

A simple experiment I encourage everyone to do to get an idea of what's going on in your aquiarium is to test the ammonia in new RO or RO/DI, then test again when salt is mixed, do a 30% water change and test the DT after one hour and again 1 day later.

reverse nitrogen cycle? sheesh, reefs are complicated.

ok, what is the point of the experiment you recommend? see how much ammonia is in the freshwater, see if any is added by the salt, and then see how long your tank takes to deal with it? in my FW world i would expect the ammonia to be gone in 24 hours in an established tank. is that what you are looking for here?