0 Nitrates so I dosed Sodium Nitrate

[Randy Holmes-Farley]

Check out this graph of phosphate vs depth in the ocean. It shows that looking at deep ocean values as a target doesn't match the surface:

http://publishing.cdlib.org/ucpress...r&chunk.id=d3_3_ch07&toc.id=ch07&brand=eschol

Vertical distribution of phosphate in the Atlantic, Pacific, and Indian Oceans based on data from the stations shown in fig. 44.

 

[Randy Holmes-Farley]

here's an example of how nutrient concentrations in surface waters in the tropical pacific do not follow the Redfield ratio if considering just nitrate and phosphate:

SURFACE NITROGENOUS NUTRIENTS AND PHYTOPLANKTON IN THE NORTHEASTERN TROPICAL PACIFIC OCEAN 1
http://onlinelibrary.wiley.com/doi/10.4319/lo.1966.11.3.0393/full

"Mean surface concentrations of nitrogenous nutrients and phosphate are reported for various areas in the northeastern tropical Pacific Ocean. Except at the Costa Rica Dome, an area of upwelling, nitrate concentrations were very low. NO3− : PO43− ratios were also generally low and phytoplankton might remove all of the nitrate while appreciable concentrations of phosphate were still present."


See table 1:

http://onlinelibrary.wiley.com/doi/10.4319/lo.1966.11.3.0393/pdf

In these studies, the Nitrate N to Phosphate P ratio is about 1 (~0.003 ppm nitrate; 0.002 ppm phosphate)

 

[Rob Lion]

Because it is a perfect analogy that shows the Redfield ratio (an uptake ratio, which is EXACTLY analogous to the uptake ratio of 18-20 ppm calcium for each 2.8 dKH of alkalinity) is NOT an aquarium target ratio and should not, buy itself, be used as such.. It is simply the ratio of elements that the organism uses.

The simple reason that the oceans don't need to have a "store" of 65dkh or 420ppm CO3 to match the 420ppm Ca is that calcium is an element/ion, the sea can not make this element from other elements, just as we can not turn lead into gold. Alkalinity is a compound/ion, it's made up from compounds and ions and elements and as such, the ocean can make this compound at will, 24/7 .... if you uptake it, more is quickly made, no need for nature to store it and nature keeps the levels balanced.

As reefers, we have a limited body of water to play with, so we often have to have elevated levels of some elements / compounds / ions etc to ensure that the important ones don't bottom out, and we typically have to dose these regularly as our tanks can not build or release what is needed themselves.

The fact that, in the article that you post, some parts of the ocean (not the part where our organisms live, by the way), happens to fall at ONE point on this ratio is meaningless (IMO). To say the ratio is desirable at any other point is just not right, as my extreme examples point out. If you want to quote concentrations in tropical ocean surface waters and give those as targets, that makes much more sense, but itself has limitations since we do not feed corals the same as they are fed in the ocean.

It is generally, in fact widely accepted, that there is a TYPICAL composition for sea water. Yes, of course real sea water all over the world and at various depths differs, but the typical quoted composition is;

<0.1 ppm Nitrate and 0.005ppm Phosphate , you even quote that yourself here >>> Reef Aquarium Water Parameters by Randy Holmes-Farley - Reefkeeping.com http://www.reefkeeping.com/issues/2004-05/rhf/index.htm

16 x 0.005 = 0.08 == <0.1 are very close to redfield.

The problem for us reef hobbiests, is in being to accurately test for nitrates and phosphates, all test kits have margins of errors, and we humans are also prone to errors. But most kits can detect to 0.015ppm PO4 +/- 0.015ppm (Hanna ULN Phosphorous and Salifert are the kits I personally use). This means if we test for PO4 and read 0, then the PO4 is in the 0 to 0.015ppm range. If we read 0.015ppm PO4, its in the 0.03 to 0 range. So the best we can test down to is 0.015ppm PO4.

Taken from your article again ;

Nitrate

Nitrate is an ion that has long dogged aquarists. The nitrogen that forms it comes in with foods, and can, in many aquaria, raise nitrate enough to make it difficult to maintain natural levels. A decade or two ago, many aquarists performed water changes with nitrate reduction as one of their primary goals. Fortunately, we now have a large array of ways to keep nitrate in check, and modern aquaria suffer far less from elevated nitrate than did those in the past.

Nitrate is often associated with algae, and indeed the growth of algae is often spurred by excess nutrients, including nitrate. Other potential aquarium pests, such as dinoflagellates, are also spurred by excess nitrate and other nutrients. Nitrate itself is not particularly toxic at the levels usually found in aquaria, at least as is so far known in the scientific literature. Nevertheless, elevated nitrate levels can excessively spur the growth of zooxanthellae, which in turn can actually decrease the growth rate of their host coral.

For these reasons, most reef aquarists strive to keep nitrate levels down. A good target is less than 0.2 ppm nitrate. Reef aquaria can function acceptably at much higher nitrate levels (say, 20 ppm), but run greater risks of the problems described above.
---------------------------

thus 0.015ppm PO4 x 16 = 0.2 == 0.2 NO3 , again redfield.

Do you really think that if nitrate is 500 ppm, that the "optimal" phosphate level is several ppm?

Firstly, I've never used the word optimal. There are way too many variables to know that.
Ok, so lets overlook the obvious silliness of a tank having 500ppm NO3, let's say that is what the Original Posters reading was.
Lets pretend his PO4 reading was just 1ppm;
500 N : 1 P

In his tank with his mad growing chaeto in his sump (and we will have to assume unlimited Carbon and Iron etc) and no other nutrients added or nutrient consumers are present, his chaeto would grow and consume 16N : 1P ... up until the phosphate was depleted, leaving him with a steady 484 N : 0 P at which point the chaeto stops growing. That's not great for the tank and the OP would be having to dose P to allow N to drop more.

By having a tank with Nitrates and Phosphates AT the redfield ratio, thus 500 ppm NO3 : 31.25 ppm PO4 his chaeto would grow... and grow.... and grow..... and grow... and his nutrients would reduce and reduce .....484 : 3.025 ...... 468 : 29.25...... 452 : 28.25... etc until BOTH N and P hit zero together, which is much better for the tank and way more controllable for the reefer. He can also slow the rate of N and P dropping by removing chaeto, which would be essential when the levels of nutrients gets lower. No need to dose Vodka etc, no need to run GFO etc.

Personally, I would aim for just above the redfield ratio, say 18N:1P to ensure that the phosphate runs out first, leaving only a little Nitrate.

So the point is, is the ratio of nitrate to phosphate important, or is it the amount of each that is importnat?

That answer is easy, it's both! having an excess of anything doesn't do the tank any favours, it's wasteful, it's inefficient and it's that "out of balance" one way or the other why this forum and all the others have the same algae or cyano issue posts. Reefers dosing vodka to lower nitrates but leaving phosphates unchecked, wondering why they get a massive cyano outbreak, or reefers using too much GFO and stripping the phosphates out leaving the nitrates unchecked and wondering why they have fast growing algae issues.

All ULNS tanks run on the ability to keep nutrients low, typically 0.2 ppm NO3 : 0.015ppm PO4 as that's the smallest we can test.

I mean no disrespect in posing my arguments to you, but for you to say that there is no merit to a tank being run at/around redfield ratios for carbon, Nitrogen, Phosphorous is wrong.... it's what the typical seawater runs at, and what ULNS reefers use, both with great success.

 

[Randy Holmes-Farley]

The simple reason that the oceans don't need to have a "store" of 65dkh or 420ppm CO3 to match the 420ppm Ca is that calcium is an element/ion, the sea can not make this element from other elements, just as we can not turn lead into gold. Alkalinity is a compound/ion, it's made up from compounds and ions and elements and as such, the ocean can make this compound at will, 24/7 .... if you uptake it, more is quickly made, no need for nature to store it and nature keeps the levels balanced.

.

I'm sorry, that just isn't making any sort of scientific sense at all.

You are claiming that the alkalinity is a certain level in the ocean because nature doesn't "need" any more?

Ignoring that for the moment, how do you think nature "makes" alkalinity?

 

[Randy Holmes-Farley]

but for you to say that there is no merit to a tank being run at/around redfield ratios for carbon, Nitrogen, Phosphorous is wrong.... it's what the typical seawater runs at, and what ULNS reefers use, both with great success.

I just cannot disagree more. Success has nothing to do with the ratio, IMO, and everything to do with the specific values. It is a subtle but critical difference because focussing on the ratio allows unacceptable values for both, and precludes perfectly acceptable values for each.

 

[Stigigemla]

The C:N:P factor varies a lot for different kinds of life. One of the lowest I have seen is 28:5.6 (https://www.ncbi.nlm.nih.gov/pubmed/17040234)
I have seen values of 50:1 and 100:1 for Caulerpa but that was in forums so I am not totally shure if that is valid.
As agriculture fertilizer is used about 16 to 20 N versus 4 P. And the uptake is about the same for orchides, tomatoes and birch.
For some vegetables we have a lower value because they use nitrogen fixating bacteria. Peas, Rhododendron and others.

 

[LV3]

I wanted to give an update to the sodium nitrate dosing I did three weeks ago. Since starting the sodium nitrate dose to get my NO3 to 5ppm, I've been able to keep the concentration anear that level despite the system consuming small amounts each week. I have noticed that the corals appear much healthier in their appearance. I'm getting growth again in my zoa frags and colonies with a baby polyp or two. Polyp extension is great right now in the system which i like to use as an indication of coral health. I'll keep updating the results in hopes that if someone reading this is or was experiencing the same issues might be inclined to try elevating their NO3 level.

 

[Waters]

This whole thread just confirms that there are much more intelligent people then me in this hobby :)

 

[hart24601]

I have found, and this is just for me personally, the best coloration I was able to get was detectable nitrate to 5ppm or so and 0 phosphate. I can actually tell when my GFO is exhausted as the coral start to brown out as phosphate levels climb, and it doesn’t take much. I also feed the coral heavily, light carbon dose for filter feeders and daily dose a little acro power. I, like many others, had corals getting light so I dosed nitrate before, but I leave phosphate alone. There seems to be plenty in the food that the corals get before the GFO does.


That is just for me and my experiences the past few years with my systems, but my last big tank did have fantastic colors. I don't care at all about the ratio - just not detectable phosphate and detectable nitrate.

 

[steallife904]

I have had 0 phosphate and 0 nitrate for some time and decided to low dose some phos and nitrate. I am wondering though if I should just focus on the nitrate right now and not the phosphate. What do you think? I think Randy told me one time I should just worry about raising the nitrate. Since my phosphates have been 0 for so long though I figured I should work on both, am I wrong here?

 

[steallife904]

and how much should be dosed a day? As for the nitrate (Neonitro) it says 1 ml NEONITRO will increase the nitrate concentration in 1 US-gallon (~3.8 L) by ~5 ppm. My tank is 150 gallons total water volume and I have been putting 1-2ml a day for about a week and about 1ml of neophos (phosphate) a day. So far both are still reading 0. Should I keep dosing low or bump it up and should I stop the phosphate dosing?

 

[hart24601]

I would just focus on one, nitrate, for the time being to see if that works well for you if you are feeding any fish ime that gives plenty of phosphate. If you get nitrate detectable and after a few weeks don't notice any great changes then I would add phosphate. I always kept phosphate undetectable with hanna ultra low and here is that tank, only white balance on the camera - no after picture enhancements:

 

[steallife904]

You have the proof it works sir! At one point in time I had a similar looking tank... then had a baby :), slacked on tank and over dosed ALK. Been fighting it ever since. Recently with advise realized that before running low nutrient worked out but after the spike it was to much stress. So now working on getting them up and with your and others advise will just focus on the nitrate.

 

[LV3]

I'm just focusing on the Nitrate as well. Since I started dosing Nitrate I have been monitoring it once a week to get a sense of the consumption from the coral and chaeto. My goal was to raise it to 5ppm and see how things looked. I dosed the full amount to get me from undetectable to 5ppm. Since then, I've seen a major improvement in the overall health of the corals and have decided to keep it there at that level. When it drops below 1ppm I does it again so I'm not dosing it every day. I don't know if it matters if the Nitrate is constantly at a specific level but for me it's too much work to find the time to dose it more frequently. Let us know how the tank starts looking after you start increasing the Nitrate.

 

[steallife904]

Any danger in dosing nitrate all at once to raise it to say 3-5? Only reason I was dosing low daily was to raise it slowly. Most stuff in the hobby needs to increase and decrease slowly so figured this was the same? Should I just dose the total amount in one shot?

 

[hart24601]

I would go slow. When I dosed previously I did a little bit each day and then a bit more and more... then boom, I had more than I wanted! I would do 1ppm per day until it's detectable and hold there.

 

[LV3]

I'd think that is a good plan as well. I raised mine from undetectable to 5ppm thinking that 5 is still pretty low overall. I didn't notice any ill effects but think a gradual increase is probably best.

 

[hart24601]

Personally I wouldn't go any higher than 5ppm. I know there are tanks that run high levels fine, but I think a lot of us, myself included, run into the trap of "if a little bit is good a lot must be ever better!" I have not noticed any dramatic color differences between detectable, 1ppm, 5ppm and 10ppm (if our nitrate tests can even really tell). Despite our systems needing a bit of nitrate, I don't think higher levels are particularly good for our other livestock health so I keep it on the lower end for color.

 

[Vaughn17]

I have had 0 phosphate and 0 nitrate for some time and decided to low dose some phos and nitrate. I am wondering though if I should just focus on the nitrate right now and not the phosphate. What do you think? I think Randy told me one time I should just worry about raising the nitrate. Since my phosphates have been 0 for so long though I figured I should work on both, am I wrong here?

I dose both with excellent results. Just make sure you have a good clean up crew, lol (except it's not funny if you don't). I keep my NO3 at about 5ppm and PO4 around .1ppm or a little less. IMO, with NO3 greater than 2ppm, acros in general don't start browning out until PO4 is higher than .25ppm. Again, that is what I experienced in my tank.

 

[steallife904]

so just tested my phosphate and nitrate. My phosphate seems like its around .01 and nitrate over 5ppm (between 5-10). should i stop dosing now and just watch how much it falls over next few days and try to keep nitrate closer to 5ppm and phos the same at .01?