Nitrate befuddlement...what would you do?

[djbetterly]

So I just received a NYOS nitrate kit in the mail today as my Elos kit was set to expire in November. I ran a test as soon as I walked in the door and was floored, the NYOS kit is reading 20mg/l. I ran it again..same thing. Never having nitrates this high I was confused, so I took out the Elos kit, again its set to expire in November, and the elos kit read between 2.5-5mg/l. This is a huge difference. Now I'm in a bind...do I do a water change or just let my chaeto eat it up and crank my skimmer to very wet?

Keep this in mind as well, I've always used this elos kit, and before when it was reading zero I was adding nitrogen to get my nitrates between 2.5-5. So in my mind I was right on track. Obviously I won't be dosing that for a long time.

Arrrgggg....Let me hear it!

 

[omykiss001]

I would first suggest a 3rd kit to confirm which might be correct. Your Elos kit is close to expiring so may be giving false reading as it get closer to its end date. If you haven't been using the Elos kit (I haven't used this one) you don't know how good or bad it might be. I think we always expect the kits to be good. It might be a bad manufacture, or the kit was not handled correctly before you bought it and some of the reagents are bad.

Maybe get a salifert kit as they are pretty reliable and on the lower price scale hopefully it would agree with one or the other. and let you know if you really have a nitrate problem. If nothing in your tank is suffering I would not make any drastic changes until you can confirm there really is an issue, or just a bad test kit.

 

[omykiss001]

Sorry I meant you haven't been using the NYOS kit, my mistake in previous post.

 

[Randy Holmes-Farley]

Another reason to not like, or overly rely on, test kits.

Without further testing, one cannot tell which, if either, is accurate.

 

[djbetterly]

I have a red sea pro nitrate kit coming tomorrow.

 

[Nano sapiens]

I'll go out on a limb and speculate (can't find a definitive answer on the Web) that the NYOS nitrate kit reports in NO3- (nitrate-ion), not NO3-N (nitrate-nitrogen) as most kits do (such as the ELOS, Red Sea, etc.).

If you divide the NYOS result by 4.4 that will give you the equivalent to the ELOS reading (which is in NO3-N). This could explain why you would get a reading of ~20 with the NYOS, but only ~5 with the ELOS kit

 

[Justiful]

I think either way you are in the safe zone. I use test strips for daily use for the big 4 and test kits for weekly use for others and the big 4. Either way I figure they are both inaccurate and as long as they don't read dangerous amounts I am not worried about it. But I am a newb, and I have an aquarium service checking every 2 weeks with entirely different tests and they seem to think things are good also.

 

[djbetterly]

@Nano sapiens that's an interesting speculation. I don't know enough about chemistry, I'm sure @Randy Holmes-Farley could chime in on that one. Either way, if that is the case, 20mg/l vs 5mg/l is a huge difference and should be noted to other users. Whatever I find out today when the Red Sea kit arrives will tell us a lot.

I do wish there was a place one could buy a set of testing standards, that would help in this case.

 

[Randy Holmes-Farley]

FWIW, nearly everyone reporting nitrate values in forums such as this are reporting nitrate ion, not nitrate-N.

The NYOS kits appears from it's card to report nitrate ion:

http://reefbuilders.com/2012/12/20/nyos-nitrate-test-kit-easily-read-scale-takes-steps/

 

[WetWhistle]

Unless you are having an issue with algae or your corals, don't stress about that number. People get stuck with chasing numbers they think they should be in or have. If you are worried just stop dosing nitrogen till you get it tested with another kit.

 

[djbetterly]

Well that's the issue, I have a bit of hair algae so I want to be sure.

 

[Randy Holmes-Farley]

In terms of algae, either 5 ppm or 20 ppm is more than enough to support such growth. Either is a lot more than in the ocean.

If you want to reduce algae by reducing nutrients, either nitrate or phosphate can work.

 

[djbetterly]

Well the confusion cloud has not been lifted. NYOS still reads 20ppm, and I checked today with a new red sea kit, using the high range test and its reading off the charts, 64ppm +++.....Going to do a water change, and I'll check it again in the AM. So confused...

 

[Justiful]

Well the confusion cloud has not been lifted. NYOS still reads 20ppm, and I checked today with a new red sea kit, using the high range test and its reading off the charts, 64ppm +++.....Going to do a water change, and I'll check it again in the AM. So confused...

http://www.amazon.com/American-Marine-Pinpoint-Nitrate-Calibration/dp/B001EHGEDU

These might work.

 

[djbetterly]

Good find! I guess I didn't google hard enough.

 

[Randy Holmes-Farley]

FWIW, those fluids are intended for calibrating the Pinpoint Nitrate probe (which I have used). While I do not know of a reason they couldn't be used for a kit, I've also not heard of anyone doing it or confirmation from Lou at American Marine that those solutions would be suitable. So while they are probably suitable, just be cautious in interpreting the results. You can always write to him and ask.

You can also make your own standards if you want using new salty water and a nitrate source, such as Spectracide Stump remover (assuming you have a scale).

 

[djbetterly]

Thanks Randy. Any chance a standard could be made from Seachem Flourish Nitrogen?

 

[Randy Holmes-Farley]

Thanks Randy. Any chance a standard could be made from Seachem Flourish Nitrogen?

FWIW, it isn't just nitrate. Part (they claim "half") of the N is something else which they elect to not clearly define from a chemistry standpoint (not uncommon for Seachem). So you might be able too, and Seachem seems to tangentially allude to this, but I can't be sure what impact that other half would have on a nitrate kit.

This is what they say:

http://www.seachem.com/Products/product_pages/FlourishNitrogen.html

"Because one-half of the nitrogen in Flourish Nitrogen™ is from nitrate you can get a reasonable estimate of nitrogen levels by doubling a nitrate reading."

 

[djbetterly]

Ok, and with Spectracide, how would I go about it? I presume this is the stuff??

I do have a scale, both gram and microgram.

 

[Randy Holmes-Farley]

Yes, that's the stuff.

Here's a plan,

Dissolve 10 grams of potassium nitrate (6.1 grams of nitrate equivalent) in 1 L of fresh water. That has a concentration of 6,100 ppm nitrate.

Add 1 gram of it into 1 gallon of artificial seawater. The concentration will be 1.6 ppm nitrate. 2 mL gives 3.2 ppm nitrate, etc.

Of course you can scale the volumes however you want, and you can reduce volumes needed by doing a 1:10 dilution of the stock solution (the 6,100 ppm) by taking 1 g of it and mix into 9 g RO/DI or seawater. That gives a solution of 610 ppm. So then 1 mL of it into 609 g of seawater gives 1 ppm, etc.