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Nitrate Levels

Shrimp seem to go through stages when they breed like mad then slow down for a while. Mine seems to slow down in winter although I can't work out how that works considering they are artificially lit and heated.

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yeah that is strange you would think it wouldn't matter and they hardly know when winter is unless tank temp drops. I see lots of females with saddles but no such look at the moment. waiting game I guess.
 
It can be tricky getting reliable figures for nitrate toxicity but I err on the side of caution and keep nitrate to less than 20ppm. The following article makes for interesting reading and then links to some scientific studies:

http://www.fishtanksandponds.co.uk/aquarium-science/nitrate.html

Although the following is only an abstract from a scientific paper, it clearly indicates that a mere 10mg/l nitrate concentration can adversely affect freshwater invertebrates, fishes and amphibians:

https://www.sciencedirect.com/science/article/pii/S0045653504009993

JPC
 
I thought of a pothos too, and water changes, if not you could change substrate or try some biohome large filter media.
 
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There is plenty scientific literature where high doses of NO2 are proven to be safe. Where high nitrate stems from ammonia-> nitrite-> nitrate the toxicity comes from the previous products.

Hi Edvet,

Thanks for your reply.

I think you meant to say NO3, not NO2 in your first sentence. But, more to the point, you say that there is plenty of scientific literature concluding that high doses of nitrate are proven to be safe. Having done a lot of searches on this topic, I have been unsuccessful finding any scientific literature in support of your statement. Would you be kind enough to let me have some internet links that I must have overlooked?

Thanks.

JPC
 
Hi all,
But, more to the point, you say that there is plenty of scientific literature concluding that high doses of nitrate are proven to be safe.
There are some links and references in <"What are your nitrate ...">.

This links to a paper on nitrate toxicity in the "Zebra Fish" (Danio rerio), where the nitrate was added as NO3-, rather than being the end result of the nitrification of ammonia.

Zebrafish are used as a <"model organism"> in the study of the genetic control of limb development etc., because the genes that control fin development in fish are the same genes that regulate limb formation in mammals.

Culturing Zebra fish is a big deal scientifically because their "neural crest cells" have many of the same characteristics of stem cells in mammals, but you have the advantages of quicker generation times, fewer ethical issues, less regulation etc.
The Zebra(fish) Danio (Danio rerio) paper use NaNO2 and NaNO3 as its source of NO2-/NO3- ions. If you convert the 606 mg/L (ppm) NaNO3 to ppm NO3- you get 442 ppm NO3- (RMM 85 and 62/85 ~ 73% NO3), so we are still talking pretty elevated levels of NO3-.
cheers Darrel
 
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Another great bit of information Edvet. Looking at the three species of fish potentially adversely affected (Oncorhynchus mykiss, Oncorhynchus tshawytscha, Salmo clarki) it is interesting to note that the toxicology expressed in table 3 (J.A. Camargo et al. / Chemosphere 58 (2005) pp. 1261) is confined to eggs and fry. The Oncorhynchus tshawytscha fingerlings had a LC-50 96hr value of 1310 mg/l NO3-N. Expressed as an NO3 value - that would be a whopping 5799.1 ppm. For a salmonid species evolved in temperate regions that doesn't sound too bad. Considering tropical fish, we can assume evolution towards a more nitrate tolerate biome. Lastly, if you look at the results you can see that sodium nitrate was validated as a method of testing toxicity. I have not read the 1976 study by Colt and Tchobanoglous that was reviewed by these authors, which these results were based upon, but I suspect the osmotic impact of sodium on eggs and fry was a highly contributory influence. These are species that spawn upstream because they are not evolved to do so in saline environments. I have yet to find a valid example implying that nitrate dosing (at EI levels) could have toxicological effects.
 
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