And here I thought I had 0 nitrates

My current inhabitants are a huge snowflake eel and a 6" volitan lionfish. It's a 75 gallon tank with about 70 lbs of liverock. I think my problem is that I used crushed coral instead if sand.

The reason for the pic was to show that I used API nitrate the whole time this tank has been setup and it always read 0. Now my new salifert test kit reads around 80.

 

Ahhhhh, thanks for the API clarification. I can't see the pic on this device.

Curious..... How long have you owned the API kit? Where did you buy it from? (LFS/online) and where did you store it?

Your problem is you have big fatty fish in that tank. It's hard to keep the nitrates down with such heavy eaters. Crushed coral shouldn't be a big issue like it can in other tanks where the food is poured into the tank. Those little bits can get caught in the crevices. If you feed whole items on a stick, you shouldn't be getting as much detritus in the cracks

Just to throw this out there in case you didn't know, not trying to be the Pred Police..... but when the volitans gets to adult size, he'll outgrow that tank. Promise that's all I'll say on that. But even with a larger tank, nitrates can be a problem.

Great choice of fish, BTW!

 

Thanks for the reply

As for the API test kit, I bought it from my LFS last year. I checked the lot number and its still good for another year

As for the lionfish, I'm moving this summer and can't take the tank with me so ill have to sell everything :'(

 

It's gonna be hard to sell that lion when they are bigger, as they become a part of the family with their pet like antics. It'll be sad. Sorry. :-(

I ditch test kits after a year.

 

Not in saltwater. Increased salinity in freshwater is actually a treatment for nitrate poisoning. In saltwater there has never been a study that has shown any ill effects from nitrate below about 500ppm. If you disagree please provide a reference.

I don't doubt that there may be a correlation between rising nitrates and RTN. Nitrates are not toxic to marine invertebrates though period (or fish below really high levels). They may drive algae and bacteria which can produce toxins or lead to pathogenic effects though. Also, there are lots of other things that tend to accumulate such as metals, which we don't test for and these come from the same sources as nitrate, so, nitrates may provide a surrogate measure of these in some cases.. So, this is semantic, but important as people have been so brainwashed into thinking nitrates are the end of the world, often the "cure" is more destructive than the nitrates. Really if everything is healthy and algae is not an issue, then nitrates are a very minor issue, if an issue at all.

 

May I be privy to your references that say marine fish are unaffected by chronic exposure to high levels of nitrate?

 

Well, I asked first but I already know the answer is there aren't any, so, in fairness, it was a trick question. Generally as has been explained to me, scientists have not been interested. There isn't a mechanism that would make nitrate particularly toxic in saltwater. It's my understanding this has been understood for a long time outside of the hobby anyways. *I think* hobbyists have a tendency to fixate on things they can test; and there does not however seem to be a particularly logical reason to do so in this case.

The is a little intrest in the scientific littersture thouh, there was a recent study:

Nitrate Toxicity to Five Species of Marine Fish Pierce et al. 2007

But no effects/death noted until 500+ppm

And the following, while focusing on freshwater, did review saltwater a bit.

Nitrate toxicity to aquatic animals: a review with new data for freshwater invertebrates
Camargo et al. 2004

From it:

"The main toxic action of nitrate on aquatic animals is due to the conversion of oxygen-carrying pigments (e.g., hemoglobin, hemocyanin) to forms that are incapable of carrying oxygen (e.g., methemoglobin) (Grabda et al., 1974; Conrad, 1990; Jensen, 1996; Scott and Crunkilton, 2000; Cheng and Chen, 2002). Nevertheless, owing to the low branchial permeability to nitrate, the NO3 up- take in aquatic animals seems to be more limited than the uptake of NHþ4 and NO2 , contributing to the rela- tively low toxicity of nitrate (Russo, 1985; Meade and Watts, 1995; Jensen, 1996; Stormer et al., 1996; Cheng and Chen, 2002; Alonso and Camargo, 2003)."


Also, RHF did put together a good review of nitrates more toxic cousin "nitrite". The biological mechanisms for nitrite toxicity is really the same as for nitrate. but more so (as mentioned in the paragraph above) and here, even nitrite, as described is not believed to be much on an issue at reef salinity.
Nitrite and the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com


There are lots of references out there however that show negative effects of algae on reef invertebrates for example. Both with regards to external benthic algae and internal symbionts. Also, there is data on metal toxicity and metal concentrations in synthetic salts and food etc... These should all go up with N. There is no evidence of direct toxicity of nitrates to any mature marine organisms though (perhaps some exception with regards to larvae or Protozoa etc... But most of us aren't trying to raise them and our filtration likely wouldn't really allow so anyways).

 

Certainly i agree with this. It was ALK with me anyway, but I still believe people needed to be testing or you don't notice the hot water until its boiling.

 

I actually wasn't talking about nitrates being toxic. That may sound like nitpicking, but here is a HUGE difference when talking about chronic levels verses toxic levels.

A "... relatively low toxicity of nitrate..", doesn't mean it can't have ill effects, just that it probably won't reach toxic levels. Anything undesirable creates stress, no matter how low and livable. Stress in itself can contribute to disease, poor growth, poor food conversion and increased mortality.

I don't perceive Randy's article a good reference when discussing nitrates in this manner. Is there a correlation in there I don't see? I don't think a freshwater article is really a great reference to a saltwater discussion either, if that's the only reference mentioned in there. I'm not home right now, but when I get settled, I'll dig out my aquaculture books. I hope I don't come off as grumpy, as it is not my intention.

 

Well, causing "ill effects". Is the sort of the definition of toxicity. There can be a difference between mortality and morbidity though, that is what I think you are getting at.

Again though, if you believe that nitrate causes morbidity at lower levels, I would be interested in a reference. They don't seem to exist outside of the realm of speculation. Also, at what level do you think chronic exposure is? 50% of a fatal level%, 30%? 10%? The LC 50 from the referenced article ranged from 500-2000ppm, but 1000ppm was more average. So even if there was an effect at 10-20% that would be in the 50-400ppm range (which as someone with training in enviormental epedemiology, i still feel is a conservative estimate).

It has a lot to do with it, it isn't just a correlation, nitrate and nitrite are both forms of inorganic nitrogen and as described in the articles i referenced these act via the same mechanisms. The only known biological mechanism, of "stress", "toxicity" or whatever you want to call it, via inorganic nitrogen (nitrite or nitrate) is described in Randy's article. In high levels this is more commonly referred to as "brown blood disease". As described in the articles I referenced, it is more of an issue with nitrite than nitrate, however, but the mechanisms are the same. In saltwater, even with nitrite which is taken up more readily and has more of an effect, is a relatively small issue because the uptake mechanism is blocked by salts in saltwater such as chlorine. While Randy's articles discuss nitrite, the same mechanisms and effects apply to nitrate (you are more than welcome to ask him if you don't believe me).

There are no other known mechanisms for why nitrite or nitrate would directly cause stress to any marine organism. As I said though, there are indirect effects, for example, increased algae growth can lead to increase carbon fixation, which can be released into the water as organic carbon. This can drive parthenogenesis bacteria and disease if high enough. Or accumulation of metals from foods may cause stress and disease and increased N etc... There are a lot of stressors in our tanks though and these N correlated ones are only an issue if other parameters allow for example.