How much Nitrate is bad?

[JSinger884]

Well my nitrate has remained around 15 mg/l and I am wondering is this necessarily bad? I was reading the information in the "tetratest" and they claim that IT IS UNFAVORABLE TO HAVE AT VERY LOW CONCENTRATIONS (>12.5mg/l). It also says that favorable levels are below 25mg/l....

 

This is pretty much the opposite of what the LFS said, which was thatI want it at zero

[spectre]

Not sure on the the conversion from mg/l to ppm but if you are housing any inverts(corals) you would like the nitrates to be as close to zero as possible. 5 ppm is a good number to shoot for. Fish are alot more tolerant to higher nitrates than inverts are. Fish can do reasonably well in as much as 30-40 ppm of nitrate. HTH

[Leonard]

1 mg/L = 1 ppm. Simple enough, huh?

 

15 mg/L is perfectly acceptable. Fact is, all animals are highly tolerate of nitrate levels, even as high as 50-60ppm. This includes inverts. The ideal that animals are highly susceptible to nitrate toxicity is a myth. NO3 is relatively beneign and causes more indirect problems (e.g. algal blooms) then direct poisoning. Ammonia and nitrite are entirely different stories.

[chufa]

15 ppm is OK. However, I disagree; high nitrates can be toxic. I learned this mostly through my FW experience with keeping africans. While organisms can survive for a long time in high nitrates, there can be bad effects, especially stunted growth and inhibition of reproduction. Also, adding an animal from a low or normal nitrate environment to a very high nitrate environment can be fatal; this is the common cause of "old tank syndrome". I don't know what would the effects be on invertebrates, but certainly I would speculate that if it is bad for fish, it would be worse on inverts, and if it is bad on freshwater fish, it wold be worse on marine ones.

[Leonard]

chufa,

 

At the fear of sounding strident, you make a lot of erroneous presumptions. First, SW and FW toxicity are not inter-related, due to the complexity of ion interference in saltwater. Just because something is extremely toxic in freshwater (I have very little knowledge of freshwater and will defer to your experience) does not mean it is very toxic in saltwater. Nitrite (NO2) is the most noteworthy of the main nitrogen compounds. NO2 is frighteningly toxic in freshwater because it binds with hemoglobins, but in saltwater, the chlorides interefere with this binding and NO2 is far far far less toxic. The exact opposite is true for ammonia. Point is, you can't make the assumption that because nitrate is toxic in FW that is also toxic in SW. This is still a largely unexplored area, but from the data gathered thus far, it indicates that nitrate toxicity is really not as significant an issue as aquarium books (fyi: most of which were based on FW) once believed.

 

Second presumption is old tank syndrome is caused by high nitrates. This rationale does not make sense to me, and is not supported by any studies. For starters, if nitrate is the primary causation, simple water changes could easily elimate OTS. It's not that easy. There are many other good theoritical explanations for OTS, a good deal of which was discussed in the following URL:

http://reefs.org/phpBB2/viewtopic.php?t=18...8675&highlight=

[Pgreco]

I too have to take issue on the freshwater post. I always understood that NItrate in freshwater was not really a bad thing. I have an african cichlid tank(which is constantly breeding) with nitrate readings that dont even register on any of the color scales, they are very. very high. This is mostly a result of my water source.

As for my saltwater nano, I have readings of about 20 ppm with thriving xenia, polyps, and mushrooms. I know that 0 ppm is ideal, but I have never had 0 ppm in any tank that I have had.

 

Just my 2cents

[chufa]

Hi Leonard:

 

I agree, that's why I used the word "speculate". It is just my opinion.

 

I had a period of poor care on my african tank during graduate school, where I was too busy, and the tank was old. Virtually anything that I added to the tank died, while the old inhabitants lived for years. My nitrates were off the scale; everything else was zero. This is common in FW, and is often called old tank syndrome, or OTS, and is mostly attributed to nitrates.

 

It has also been documented that delicate africans from lake waters of low nutrient content are sensitive to nitrate (Loiselle, Cichlid Aquarium), and that excessive nitrate stunts growth and inhibits proper reproduction.

 

So given that excessive nitrate can have bad effects in FW, why not speculate that it could in SW?

 

Besides, I am talking about too much nitrate. Perhaps levels of nitrate which were once believed to be toxic are not. But at some point, too much of anything can alter the chemical composition of the water to the point of being toxic.

[Leonard]

Why not speculate? Well, here goes:

 

While I can see where you're coming from, I have to once again insist that no such speculation should (or can) be made. Toxicity in saltwater and freshwater behave very differently, and nitrate is no different. As I mentioned, I am not very well-versed with freshwater husbandry, but I am confident high nitrate levels (as high as 60ppm) are not acutely or chronically toxic to marine organisms ... at least not the species we intend to keep. Granted, beyond a threshold, nitrate will be toxic. But that's true for any matter. Toxicologist will tell you that all compounds are poisons ... just depends on the concentration! I just wanted it be known that nitrate isn't as horrible as most people have been led to believe. Now don't get me wrong .... nitrates can cause a plethora of indirect problems (algae blooms come to mind immediately). But it, itself, is not very toxic (NO3 is a relatively stable compound).

[JSinger884]

Well I must say I did not expect such a sophisticated debate on this thread! But I am now inspired to run a research project on the subject to answer this seemingly complex question.

 

The experiment: "Are nitrogen compounds, specifically nitrate, as toxic at high levels in a saltwater tank as they are in freshwater?"

 

I have no idea how I am going to carry out the research, so any suggestions from all of you would be great! Also if anyone has any extentions to this idea they think would be relevant, do not hesistate to tell me.

 

Thanks everyone

[Leonard]

The only thing you can really experiment for is acute toxicity. You have to set up a bank of tanks, all with controlled constants (water used, temperature, volume, etc.). Then you vary the NO3 level of each tank, making sure the NO3 levels are constant throughout the duration of the experiment. Then select a candidate species to be your test subject. Clownfish are ideal because you can purchase multiple specimens from the same spawn, ensuring as little genetic influence as possible. They're also fairly cheap. The more per tank, the better ... no less then 10 specimens per. Now, the only thing left is waiting to see who dies when. When half suffer mortality (standard LC50 = lethal concentration that kills 50%), you have the data you are after. Other interesting/useful data is when first mortality ensues, and when last one happens(could be indefinite).

 

It's a big undertaking to do it right. Controlling the constants along is tough enough. Not sure how you will maintain said nitrate levels (or how to get them to the deisred levels in the first place). Plus, to get accurate results, sample sizes really should be very large.

 

Hope this helps.

[JSinger884]

That really does help a lot and I appreciate your input. Although, perhaps I should try using a different creature...am I legally allowed to experiment on clownfish?? I am planning on doing this on a formal level in attempt to earn some college scholarship money.

[Leonard]

Sure, clownfish are perfectly legal to experiment on. In fact, I find their the best candidates since they have large spawns and are fully cultured (no impact to the environment). A.ocellaris is probably the best bet. Most tropical marine experiments use A.ocellaris as their test subject as a matter of practicality.

 

Of course, wild specimens may be more accurate (operative word is "may"). But they too possess many problems of their own(interspecial genetic diversity, cost, environmental impact, et. al.)

 

Go with cultured.

[JSinger884]

Thats definatly good to hear. Now for a series of questions...

 

1. How big should each tank be?

 

2. Will a denitrifyin filtration system (i am not sure if thats what its called) work to control the nitrate levels?

 

3. Will live rock and sand have an effect on nitrate levels? And could I use them to control nitrate levels in the experiment?

 

4. A. What equipment will be necessary for this endeavor?

 

B.What will the approximate cost of the experiment be?

[chufa]

Oh no! poor clownfish used as lab rats! Why not use domino damsels instead? Less expensive, plentiful, and quite a problem since a lot of people buy them and return them.

 

Also, I must admit after reading the discussion on other posts that the concept of OTS is quite different in SW than in FW.

[MrConclusion]

Well, here's another theory about "old tank syndrome" and I actually have the math to back it up. I've gotten away from the practice of doing small volume "low impact" water changes. Here's what made me decide to change more water volume:

 

There are lots of different pollutants/contaminants building up in any tank. Some of them are natural biological products, some of them are impurities from foods, additives, and make-up water. Some may even be airborne (look at what comes out of a vacuum cleaner under a microscope... ugh!)

 

We can bicker about exactly what is building up, and how fast, but the fact is that there is some kind of steady buildup of stuff that you don't want in your tank.

 

Add all of this stuff together, and call it "substance-X" where X is the contamination/pollution factor.

 

How much of substance-X is building up between each water change? It doesn't matter what the w/c interval is... a week, a month, whatever. Call the buildup amount of substance-X one unit. Therefore, between every water change, 1 unit of X is building up.

 

Now here's the cool part. Before your first water change you have 1 unit of X in your tank. If you change 20% of your water, you have 0.8 units of x in the tank. X continues to build up, so at the next water change you have 1.8 units of X. Change 20 percent again and you now have 1.44 units of X. See how it can gain on you?

 

Eventually, however, you reach a point of equilibrium. Here's how it works out:

 

10% change, stable after 60 w/c cycles at 8.985444217 units of X

15% change, stable after 40 w/c cycles at 5.659430582 units of X

20% change, stable after 24 w/c cycles at 3.984888427 units of X

25% change, stable after 20 w/c cycles at 2.992864773 units of X

30% change, stable after 18 w/c cycles at 2.331471514 units of X

35% change, stable after 16 w/c cycles at 1.855257216 units of X

40% change, stable after 12 w/c cycles at 1.498824538 units of X

45% change, stable after 10 w/c cycles at 1.220519516 units of X

50% change, stable after 24 w/c cycles at 1.220047466 units of X

 

Again, I'm not making any claims as to what X is (nitrate, copper ions, windex, hand lotion, dust, etc.) But there are far, for more nasty substances that can build up in your tank than there are test kits available for them.

 

And the actual amount in each unit doesn't matter. If your tank was producing 2ppm excess nitrate between each 20% water change, you're eventually going to stabilize at about 8 ppm.

 

This also assumes a mature tank where no new colonies of de-whatevering bacteria, algae, etc are growing. I did this math a while ago and it made me decide to start doing 40% water changes on FO tanks and 30% on reefs (every 2 weeks), and all tanks have been happier for it.

 

Thoughts?

[hooked]

I agree with the statement that high nitrates will stunt the growth of fish. I had a 38g reef that for 8 months had a nitrate reading of 100ppm, that is correct 100ppm. Before I got good solid information I thought that high nitrates didn't have any impact on my tank. I have a maroon clown that is in my 90g gallon now but for 8 months he was in the tank with high nitrates. He didnt grow more then 1/4 inch. I was always wondering why he wasn't growing but from reading all the post it makes sense. From my experience the high nitrates had no effect on my corals. I had a cup coral, fox coral, soft tree coral, open brain, star polyps, and some others. I never had any coral problems at all. About a month before I took the tank down my soft tree coral actually divided ( broke off limbs ) 3 times. I still have the 3 pieces that broke off in my 90g and will be putting into my 2.5g. Everything in my tank looked good with the nitrates so high.

 

It took me 3 months of 5% weekly water changes to get my nitrates down to 10ppm.