nitRATES

What exactly is the toxic level of nitrates??? What is considered unsafe?

I know the everglades is partially being destroyed by the overabundance of nitrates from fertilizers... which causes plants to overgrow and choke out the native lifeforms.

However... as far as our litte ecosystems are concerned... what is the level that could actually harm the fish??? Mine always test high. I do weekly water changes and gravel vacs and clean my filters and they always seem to stay around 40 no matter what i do. So ive given in... i will do my regular maintenance and let the nitrates be what they will be. Sometimes before a water chagne ive tested them higher, around 60-80ppm with no obvious distress on the fish. So is it toxic at these levels?

I know what yall are going to say "do more frequent bigger water changes" blah blah blah.. thats not what im asking. I do weekly water changes and i used to do them mroe often but always have the same results and i even bought 3 different nitrate test kits to make sure.. lol. But I keep up with my weekly maintence to keep them from getting off the charts.

So the question is.. what is the lethal limit of these nitrates? How harmul are they? we all know ammonia interferes with respiration and can burn them right? So what exactly does nitrate do to harm? Any articles would be appreciated as well.

[bzbee]

http://www.novalek.com/kpd47.htm

I was surprised to find out this product even existed as I never let my nitrate go beyond 40ppm, but if you believe the contents of this ad : "tolerances to nitrate toxicity vary greatly (some species can tolerate an indication of 300-400 ppm or more) the concentration should be kept well below 100 ppm: 35-70 mg/L nitrate would be better for most freshwater fishes. Saltwater fish and invertebrates should be kept in water with no more than 20 mg/L nitrate"

HTH!!!

[czcz]

From a google search for "nitrate toxicity fish"

A group of Spanish chemists have published a review of the toxicity of nitrate upon aquatic organisms... The review, which looked at marine and freshwater invertebrates, fishes and amphibians, suggests that the main toxic effect of nitrate is due to its ability to convert oxygen-carrying pigments to forms that are incapable of carrying oxygen.

A similar process occurs with nitrite, in which the chemical oxidises haemoglobin to methaemoglobin which has no oxygen-carrying capacity.

The authors claim that nitrate is more toxic at higher levels and when animals are exposed to raised levels for long periods of time.

http://www.practicalfishkeeping.co.u...m.php?news=560

The data presented here support the theory that prolonged exposure to elevated levels of nitrate may
decrease the immune response, induce hematological and biochemical changes indicative of a
pathologic response, and may increase mortality.

http://72.14.203.104/search?q=cache:...ient=firefox-a

In order to investigate the effects of short-term exposure to nitrate, one-month-old Medaka fish was exposed to NaNO3 at concentrations of 100 and 125 mg NO3-N l-1 for 96 hours. At the end of the exposure period, survival rate was found to be 30% and 10%, for the 100 and 125 mg NO3-N l-1 exposure concentrations, respectively.

http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract

[Devilishturtles]

I think everyone else pretty much summed it up. It varies between species. I also think it varies upon the health of the species as well. When I got sick a few weeks ago, I slacked on tank maintenence a lot for the month or so I was out. In my sw tank, my nitrates climbed to over 160 ppm...but, I lost not a single invert, fish, coral species, etc. (By the way, not codoning this action. ) I let that happen in my fw tank last year or so, and lost an angelfish, clown loach, and 2 snails.

I think to be safe, keeping nitrates under 40 ppm is good. Preferably less. Lower nitrates lets your fish grow to their full potential growth.

[Andos99]

Mine always hovers around 40 ppm as well. There was a pretty good article in AFM this month about this very thing. It talked about mature tanks and how most issues arise between months 6-12, which at this point, a 20% water change becomes obsolete (PWC's must be much larger to sustain nitrate levels). Not saying you have this problem, but it was a good read if you're a subscriber. I've heard of an instance of someone testing 500+ nitrate levels with fish still alive (not sure of the species or their overall health). Sorry for the ramble.

[TomK2]

Isn't there a giant dead zone in the gulf of mexico, that kinda sticks out a few hundred miles from where the Mississippi river runs into it? I have been told that this giant dead zone is from fertilizers and other run-off into the Miss. River, and these products cause bacteria and algae to bloome in the Gulf to such an extent that oxygen is consumed. Thus, no higher life forms due to oxygen depletion. The dead zone is rather huge, too.

But on a lighter note, my nitrates rarely get to 10 ppm in my tank. Lots of water changes.

[Devilishturtles]

Dinoflagalette poisoning is a big issue causing red tides and such that starve the water of oxygen and cause a menagerie of other issues. They only do that with the right conditions though ie: high nutrients, right temperature, etc.

I did a research presentation on this subject for school last semester. It really opened my eyes to what they are doing to animals, plants, humans even.

[TomK2]

Here's links about the dead zone:

http://news.nationalgeographic.com/n..._deadzone.html

http://www.smm.org/deadzone/

http://www.sciencenews.org/articles/20040605/bob9.asp

[crazyred]

Ashley, have you checked your tap water for nitrates? I know that on a lot of other boards I visit (none as good as this one ) that when a person is having nitrate issues in a normally stocked and maintained tank a lot of time the problem is nitrates from the tap. That would render your PWC ineffective since you would be adding nitrates just by doing them. Give that a check and maybe you could look into partially diluting your tap water with RO/DI if you do have nitrates.