Nitrite Level in Established Reef Tank

[Matt L.]

Okay,

Has anyone ever wondered what the nitrite level would be in an established reef tank? Conventional wisdom says zero, but is this really the case? As I found out, the answer is most certainly no.

Using the the Griess reaction and absorbance at 540nm in a spectrophotometer, my reef water tested at 0.038ppm Nitrite-N. That's not high enough to impact the fish, but certainly far from zero as well.

Such a low level of nitrite must be the background level of a cycled tank. The cycle is working perfectly, but at any given time, there is a low concentration of nitrite and ammonia intermediates.

I'm now curious what the ammonia concentration is...

Matt

 

[delta]

Okay,

Has anyone ever wondered what the nitrite level would be in an established reef tank? Conventional wisdom says zero, but is this really the case? As I found out, the answer is most certainly no.

Using the the Griess reaction and absorbance at 540nm in a spectrophotometer, my reef water tested at 0.038ppm Nitrite-N. That's not high enough to impact the fish, but certainly far from zero as well.

Such a low level of nitrite must be the background level of a cycled tank. The cycle is working perfectly, but at any given time, there is a low concentration of nitrite and ammonia intermediates.

I'm now curious what the ammonia concentration is...

Matt

It only makes sense that this is the case based on the way ammonia is broken down at all/some times there has to be trace amounts of ammonia nitrite and nitrate. I think the term "Zero" is a miss used value in this case

 

[Moe_K]

Zero should be read as not detectable when using common hobbyist test kits.

 

[naturebatslast]

On my spectrophotometer, I picked it up at Goodwill, I tested only 0.036 ppm of nitrite.
Going back to the home kits, I think you have to think of it in significant digits, and it seems home kits only have one sig fig compared to your office rig. But, it is good to know.

 

[nitrofish]

you consider that far from zero?

this is a fish tank where talking about, not a laboratory

 

[JohnK]

Matt, your just showing off , I'm with Moe, I read .038 as undetectable.

Pretty soon someone is going to ask about a group buy on spectrophotometers.

 

[NateHanson]

That's only a high number if ocean water on the reef is significantly lower.

So fly to the Solomon Islands (I'm sure your PI won't mind footing that bill ), and collect a dozen samples, then test your tank a dozen times, and see if there's a statistical difference. Then we can talk!

 

[Greg Hiller]

My old 110 Gallon reef would run with moderatly high nitrates all the time. I never considered it really an important number. I stopped measuring it years ago.

I've seen graphs of ammonia concentration in a reef tank and it basically oscillates a lot. Goes up after you feed the fish and they start to pee. Goes back down quickly in an established reef as corals, clams, bacteria take it up.

 

[Matt L.]

On my spectrophotometer, I picked it up at Goodwill, I tested only 0.036 ppm of nitrite.

I actually found this one in the garbage. Honest.

In order to sell it on eBay, I wanted to prove it worked first. After all, I found it in the garbage here.

I decided to make a calibration graph for something, and it just so happened the Griess Reaction for quantifying nitrite was a real easy and practical manner to go about that. You combine a fixed amount of color agent and varying amounts of sodium nitrite and you get a real pretty magenta colored product.

I had an extra reaction tube, so I just used some tank water to see what the level of nitrite really was.

I most certainly would not bother testing for nitrite any other time.

Going back to the home kits, I think you have to think of it in significant digits, and it seems home kits only have one sig fig compared to your office rig. But, it is good to know.

Yeah, home test kits for nitrite are probably only accurate to one significant figure. I think Salifert makes one that can test down to 0.002ppm, but again, your answer would only be to one significant figure. I rounded to two significant figures, and just thought I'd share the answer here.

Matt

 

[Matt L.]

...I'm with Moe, I read .038 as undetectable.

I would say it is insignificant rather than undetectable. In the method I was using, a concentration of 0.038ppm as N is most certainly detectable -- it is just insignificant. I thought I'd just share the answer.

...Pretty soon someone is going to ask about a group buy on spectrophotometers.

I probably shouldn't say this here, but the whole reason I went about testing for nitrite was because someone had thrown one away at the University, and I wanted to test it before putting it up for sale on eBay,

Matt

 

[JohnK]

Gee, what does one of those things go for?

 

[Matt L.]

A used Spectronic 20D like the one I found? Probably $500 from an online store.

I don't think I'll be able to sell mine for near that.

I'm keeping the better one I found previously.

After I put this one up on eBay, I thought it might have been better to try and sell it over on RC,

Matt

 

[Greg Hiller]

Oops, sorry about my post, I didn't realize you were talking about nitrite.

 

[Matt L.]

That's okay. When we're talking about this on the phone, we call nitrite as "N-O-two" and nitrate as "N-O-three" because I deal with both, and a little mistake can make a big error!

 

[NateHanson]

Hehe, I read it as nitrate too.