Ammonia, nitrite, and nitrate levels before adding first fish.

[commod0re]

To clarify, that is nitrite-N. Not ppm nitrite.

I also think there is something possible misleading about the table.

It only lists a few marine species, and only a couple are as susceptible as you suggest, but weirdly, one that does show tox as low as 30 ppm nitrite shows a massive range (white shrimp 9.0-322.0 mg/L nitrite-N).

But then it says

Some of the variation in toxicity relates to the species’ differences in nitrite susceptibility. For example, the 96-hour LC50 in Pacific white shrimp at 35-ppt salinity is 322.0 mg/L, while at the same salinity, the value for black tiger prawn is only 14.0 mg/L. At a chloride concentration of 22.0 mg/L, the 96-hour LC50 for channel catfish is 7.5 mg/L, while for fathead minnows, it is 70.0 mg/L.

Which leads me to believe that the low values of LC50 for the white shrimp are not actually at 35 ppt, but at a lower salinity.

These are good points. I am not trying to stack these numbers up against your own data because I consider you as a source to be both more pertinent and reliable. It does establish at least that the LC50 is not the same for every species though, and could potentially differ by large amounts. But we have a lot of missing information in this area imo:
Maybe it takes 1000 ppm to potentially kill a given species within 4 days bur what about 14 days? 30 days? what’s SC50 (S=stress)? These things are not so clearly established and so I wonder at why we should be so confident that they don’t matter at all…

Put another way: the LC50 for brussels sprouts might be >40 lbs but if you hate them, it might also only take a few grams to increase your stress level and if that’s all you’re getting for every meal that could get worse

 

[Randy Holmes-Farley Verified Community Expert]

I’m not asking you to revise your opinion but I think we can at least agree that death is not the only possible outcome that could be considered harm and that implication is what I’m challenging today. If an aquarist is aware that it presents a slight risk and chooses to take that risk I wouldn’t balk at it. What I find odd is bringing it up as a possibility and then being told repeatedly that that is impossible, but the only thing any of you can back it up with are the same lethality statistics that I already also mentioned lol

It is certainly true that other effects may happen at levels lower than needed for death, and in my article linked above I show other endpoints. These include “safe level for rearing”, “growth rate” “noticeable effects”, etc.

I showed all data that I could find for marine organisms at the time.

 

[Randy Holmes-Farley Verified Community Expert]

These are good points. I am not trying to stack these numbers up against your own data because I consider you as a source to be both more pertinent and reliable. It does establish at least that the LC50 is not the same for every species though, and could potentially differ by large amounts. But we have a lot of missing information in this area imo:
Maybe it takes 1000 ppm to potentially kill a given species within 4 days bur what about 14 days? 30 days? what’s SC50 (S=stress)? These things are not so clearly established and so I wonder at why we should be so confident that they don’t matter at all…

Put another way: the LC50 for brussels sprouts might be >40 lbs but if you hate them, it might also only take a few grams to increase your stress level and if that’s all you’re getting for every meal that could get worse

If someone has any data suggesting nitrite at 10 ppm or less (I have never seen more than a few ppm reported) cause harm in a newly cycled reef tank to the first fish folks want to add, then this is an important issue.

We are looking at levels 10-100+ times lower than the lethal dose. How many other chemicals would that apply to? Even sodium and chloride will kill at 10 times the normal concentration.

 

[commod0re]

It is certainly true that other effects may happen at levels lower than needed for death, and in my article linked above I show other endpoints. These include “safe level for rearing”, “growth rate” “noticeable effects”, etc.

I showed all data that I could find for marine organisms at the time.

For some reason the link still does not load for me. I trust you, I just can’t actually see it, and I’m not sure why :(
It has also never shown up in search results for me for some reason, but google’s index has also been going to ****

If someone has any data suggesting nitrite at 10 ppm or less (I have never seen more than a few ppm reported) cause harm in a newly cycled reef tank to the first fish folks want to add, then this is an important issue.

We are looking at levels 10-100+ times lower than the lethal dose. How many other chemicals would that apply to? Even sodium and chloride will kill at 10 times the normal concentration.

Fair enough. I definitely haven’t seen anything like that. Would you say that 10 ppm would be the point at which to begin being concerned then?

 

[commod0re]

@Randy Holmes-Farley oh I do have this recent personal observation though: I moved fish into my current tank after the ammonia cycle was ready but before nitrite actually reached zero, and nitrite still has not reached undetectable levels on a salifert test after over 4 months. This was not the case with the previous tank where we also waited a bit longer to start adding fish so I assumed that the reason for this extended cycle was because I added the fish before the bacteria was truly ready. I have never recorded a result from the salifert test above 0.25 ppm, sometimes as low as 0.01 but never 0. The old tank nitrate hit undetectable before we added fish, which only added an extra two weeks of nitrite being present and potentially affecting the nitrate test, vs 4+ months this time… did I do something wrong that I am unaware of? Am I crazy? Or could I have avoided some issues and wasted reagents by waiting it out the extra 2 weeks up front?

 

[Randy Holmes-Farley Verified Community Expert]

Try this web archive link. The original is slow.

https://web.archive.org/web/20220523235603/reefkeeping.com/issues/2005-06/rhf/index.htm#6#6

 

[Randy Holmes-Farley Verified Community Expert]

@Randy Holmes-Farley oh I do have this recent personal observation though: I moved fish into my current tank after the ammonia cycle was ready but before nitrite actually reached zero, and nitrite still has not reached undetectable levels on a salifert test after over 4 months. This was not the case with the previous tank where we also waited a bit longer to start adding fish so I assumed that the reason for this extended cycle was because I added the fish before the bacteria was truly ready. I have never recorded a result from the salifert test above 0.25 ppm, sometimes as low as 0.01 but never 0. The old tank nitrate hit undetectable before we added fish, which only added an extra two weeks of nitrite being present and potentially affecting the nitrate test, vs 4+ months this time… did I do something wrong that I am unaware of? Am I crazy? Or could I have avoided some issues and wasted reagents by waiting it out the extra 2 weeks up front?

I don’t know why you saw an extended detectable nitrite. Might be due to the species present at the start, the available of other needed elements by the nitrite reducing organisms, test error, or something else.

 

[commod0re]

I don’t know why you saw an extended detectable nitrite. Might be due to the species present at the start, the available of other needed elements by the nitrite reducing organisms, test error, or something else.

I don’t think test error, I am careful about following the procedure in the instructions, salifert tests are pretty straightforward, it has remained the case over a number of repetitions, and I also verified the test against another tank, but I suppose I have no way to test any of the other things you mentioned aside from phosphate which I have maintained at about 0.14 +/- 0.02 per hanna checker (ULR)

 

[commod0re]

Try this web archive link. The original is slow.

https://web.archive.org/web/20220523235603/reefkeeping.com/issues/2005-06/rhf/index.htm#6#6

Thanks this one works. Notably there are a couple of inverts in your tables that do suggest measurable consequences at levels below 5 ppm, green sea urchins in particular at 1.6. Also notable are the entries that clearly benefit from nitrite availability such as abalone. Nevertheless it is clear that this supports the idea that many/most marine fish will not even notice a bit of nitrite. Thank you for taking the time to expand my understanding

 

[Randy Holmes-Farley Verified Community Expert]

You’re welcome.

Happy Reefing!