So my water DOES need nitrates now??

[willthethrill]

I was at the point you were at when I came to the same conclusion. I went from 40 or 50 to zero over the course of a few months by doing a variety of different things. When I finally got down to undetectable or near undetectable for a period of time my softies especially started to look worse. As I backed off it was interesting to notice how some corals looked better with lower nutrients and some looked worse. I found a balance around 5. I don't feed much and only use coral food once a week. Seems to be working well.

Yup. My euphylia coral are always half out. They used to be all plumb and fully extended swaying in the current when my system was newer and now they look dull. I change their positions weekly hoping they find a comfy spot again.

 

[willthethrill]

I'd leave your reactors online if you are increasing food input. One change at a time so you don't swing to fast the other way. Just my thoughts.

Yea that was my main concern. I'm leaving them online and just feeding heavier in combination with dosing reef energy while I wait for the new fish to be done with the QT process. Once they're in the display it'll be an extra bio load.

 

[mcarroll]

I change their positions weekly

Moving them is rarely a good option.

 

[Hans-Werner]

In my opinion nitrate is not necessary at all as long as there are other forms of nitrogen available like ammonia, amino acids, urea or other forms of organic nitrogen. The corals can even make some of the nitrogen they need themselves since they have symbiotic bacteria which fix N2 (dissolved dinitrogen gas) and make it available to the corals.
Some forms of nitrogen are usually present in concentrations sufficient for corals in nearly every tank with some fish. The minimum concentrations of ammonia corals need are very low since they can take it up from very low concentrations and fish excrete ammonia. Besides this nitrogen seems to be the nutrient that makes corals getting brown and making algae grow.
A minimum level of phosphate is much more important to corals. Recent scientific research has confirmed this. I would call a system with 0.01 ppm to 0.05 ppm PO4 a LNS or ULNS and 0.05 ppm to 0.1 ppm is a save low level for most systems.
In contrast to common believe I think that SPS need more phosphate and a more continuous phosphate supply than most other corals. It seems to have something to do with the rapid growth and maybe rapid calcification.

 

[MickMurray]

Quick question: which test kits should be used?

 

[mcarroll]

@Hans-Werner good link!

It's interesting to me that you don't necessarily need recent research to understand this about phosphates...as usual (so it seems) the hobby is decades behind the science.

I think you could have also pointed out that if corals can feed on particulate matter (e.g. zooplankton, detritus, etc) it may not depend as much (or at all) on dissolved or translocated nutrients.

Stuff you may or may not find interesting....

From the links and charts in post #58 from one of our diy amino acid threads, nitrates are actually a significant source of nitrogen used for growth, along with ammonium. Urea and amino acids are minor sources. The only thing that makes either nitrate or amino acids interesting to us is easy availability and ease of handling.

From post #64 in that thread:

"Nitrogen cycling in corals: the key to understanding holobiont functioning?"
http://dx.doi.org/10.1016/j.tim.2015.03.008

Along with the earlier link (repeated below again), these two articles make a good combo!

"Uptake of dissolved free amino acids by the scleractinian coral Stylophora pistillate"
http://dx.doi.org/10.1242/jeb.012807​

As for low-phosphate conditions....

From post #100 of the "Nutrient Saturated Systems" thread:

Just found out that some "algae" can turn into bacterivores under low phosphate (nutrient starvation) conditions.

Low P conditions also seem to cause them to become more toxic.

These are single-celled "algae" – obligate primary producers was the focus.

"Bacterivory in algae: A survival strategy during nutrient limitation"
http://aslo.org/lo/toc/vol_38/issue_2/
Download

Here's the Abstract just to get you warmed up, if you weren't already:

Bacterivory in obligate phototrophic algal flagellates may be an important strategy for acquiring nutrients during periods of inorganic nutrient limitation. Several marine algal flagellates were shown to increase bactivory when phosphate was limited. Grazing on bacteria by algal flagellates was found during blooms of Prymnesium parvum in Sandsljorden, western Norway, in 1989 and Chrysochromulina polylepis on the south and west coast of Norway in 1988. Dissolved phosphate was not detectable in these situations. Algal flagellates may graze bacteria to obtain phosphate, which may permit these algal flagellates to develop blooms when phosphate becomes limited.​

From post #15 in the Can't get rid of no3... thread:

High phosphate uptake requirements of the scleractinian coral Stylophora pistillata​

 

[Hans-Werner]

Matt, the last article linked I already knew. I also have discussed the theme with one of the authors and have given my observations in reef aquaria.

Bacterivory in dinoflagellates is also not new to me but I didn´t know about the connection to phosphate limitation (or forgot about it). Yes bacteria are superior to algae in their phosphate uptake at low concentrations presumptively due to big relative surface at small volume.

Already Sorokin has written in his book in 1995 that scleractinians are phosphate limited which he found out with tracer experiments. My first conclusion then was that they also should be phosphate limited in the tank and made according experiments until I found out that it is better to have some phosphate in the tank and keep the SPS rather nitrogen limited or colimited if nutrient limited at all.

 

[mcarroll]

Most of the articles I've collected with "revolutionary" information in them date from the 1990's or before....some as early as the 1930's. The state of the art is rather dilapidated compared with the available information.

Glad to have Reef2Reef so these aren't private discoveries like they've always been in the past.

 

[bif24701]

Most of the articles I've collected with "revolutionary" information in them date from the 1990's or before....some as early as the 1930's. The state of the art is rather dilapidated compared with the available information.

Glad to have Reef2Reef so these aren't private discoveries like they've always been in the past.

I think the reason we have begun to evolve our thinking is because our methods, equipment, husbandry, and aquaculture have evolved to a point where we can begin to focus more on the animals we put in our biospheres rather than combating endless problems that came from the inferior process. Now we are learning to keep them and let them thrive, and even manipulate the traits we desire.

 

[Hans-Werner]

There is another very interesting article about nutrient limitation in corals. I have the article including a supplement with additional photographs which can even be used for a kind of diagnosis. The article says if you supply additional nitrogen (DIN) to a phosphate limited coral it may cause damage, tissue loss and death to the coral which is not the case at the same phosphate concentration without added DIN. This is why nitrate should never be added to a phosphate limited coral.

 

[Rick.45cal]

There is another very interesting article about nutrient limitation in corals. I have the article including a supplement with additional photographs which can even be used for a kind of diagnosis. The article says if you supply additional nitrogen (DIN) to a phosphate limited coral it may cause damage, tissue loss and death to the coral which is not the case at the same phosphate concentration without added DIN. This is why nitrate should never be added to a phosphate limited coral.

That's a great article! Thankfully they actually posted what they were considering as "low nutrient", "nutrient replete" and "imbalanced nutrient"

Anyone who is a little quicker on the draw (than me) care to try and convert their micromolar measurements to ppm. I understand that the DIN is a composite of 90% Nitrate 10% nitrite and negligible NH4

Here's what they list:

Different units of the tank system were adjusted to low-nutrient (DIN ∼ 0.7 μM/phosphate ∼0.006 μM), nutrient-replete (DIN ∼6.5 μM/phosphate ∼0.3 μM) and imbalanced-nutrient (DIN > 3 μM/phosphate ∼0.07 μM) conditions15 .

 

[Rick.45cal]

It's been awhile since I've exercised the chemistry conversion side of my brain. I did some figuring of the above concentrations and came up with:

"low nutrient" system
NO3 39 mg/L
NO2 3.2 mg/L
PO4 0.57 mg/L

"Nutrient Replete" system
NO3 362.7 mg/L
NO2. 29.9 mg/L
PO4. 28.49 mg/L

"Imbalanced Nutrient" system
NO3 >167.4 mg/L
NO2. 13.8 mg/L
PO4. 6.648 mg/L

Anyone care to check my math?

EDITED TO ADD: THESE ARE INCORRECT FIGURES DUE TO A SIMPLE CONVERSION ERROR DISREGARD THEM PLEASE (forgive my mistake, please)

 

[willthethrill]

It's been awhile since I've exercised the chemistry conversion side of my brain. I did some figuring of the above concentrations and came up with:

"low nutrient" system
NO3 39 mg/L
NO2 3.2 mg/L
PO4 0.57 mg/L

"Nutrient Replete" system
NO3 362.7 mg/L
NO2. 29.9 mg/L
PO4. 28.49 mg/L

"Imbalanced Nutrient" system
NO3 >167.4 mg/L
NO2. 13.8 mg/L
PO4. 6.648 mg/L

Anyone care to check my math?

I'll take your word [emoji28]

 

[bif24701]

It's been awhile since I've exercised the chemistry conversion side of my brain. I did some figuring of the above concentrations and came up with:

"low nutrient" system
NO3 39 mg/L
NO2 3.2 mg/L
PO4 0.57 mg/L

"Nutrient Replete" system
NO3 362.7 mg/L
NO2. 29.9 mg/L
PO4. 28.49 mg/L

"Imbalanced Nutrient" system
NO3 >167.4 mg/L
NO2. 13.8 mg/L
PO4. 6.648 mg/L

Anyone care to check my math?

Could you possibly convert those to ppm?

 

[Rick.45cal]

I'm hoping someone else will crunch the numbers. I find some of the concentrations they offered at the end of that article to be very strange.

For what it is worth mg/L should be equal to ppm.

 

[Rick.45cal]

No! My numbers are wrong!!! I made a conversion error!!! Pay no mind!!!

WHOOPS!!! Sorry folks

 

[Rick.45cal]

Ok, so I fixed my mistake

"Low Nutrient" system
NO3 0.039 mg/L
NO2 0.0032 mg/L
PO4 0.00057 mg/L

"Nutrient Replete" system
NO3 0.363 mg/L
NO2. 0.0299 mg/L
PO4. 0.028 mg/L

"Imbalanced Nutrient" system
NO3 0.167 mg/L
NO2. 0.0138 mg/L
PO4. 0.0066 mg/L


That makes more sense, and I now understand the article much better. Sorry you all had to suffer through my conversion error!

 

[Phil Cusimano]

I've found that there are all sorts of variations out there on this topic. Here's what I've learned in this regard:
- The ocean's nitrate levels are pretty low - anywhere from 0.1ppm - 2.5ppm (or less, or more).
- Most test kits are only accurate to around 0.5ppm at best.
- Getting nitrates up shouldn't be hard (over-feed the tank or dose it in).
- Raising your nitrates will raise the potential for algae growth.

So, from what I can glean:
Having SOME nitrate is closer to the natural ocean, but getting an accurate read on just how much you have in your closed system, at levels low enough to match the ocean can be tricky to do in the best of cases. And if you can't get an accurate read, your ability to control is difficult (potentially impossible). Which makes aiming for anything >0 nitrates (or >0.5ppm, really...) a bit of a gamble - if you win, you get a tank that's like the ocean; if you loose, you are basically feeding bothersome algae.

Personally, I had 0 nitrates in my tank and then read a bit about dosing it in being a Good Idea. So I mixed up some Spectracide and calculated my dosing level. I was able to hold it between 3-4ppm. A few weeks in, I started to see more algae growth than I ever had before, so I stopped dosing in nitrates. It's entirely possible that the algae entered the system via some other means and just took advantage of the food available to grow. It's also possible I started feeding more as I added more fish and that caused it. Or else something else entirely... Basically; I didn't have good luck with elevating my nitrates, but I was also pretty far from having a controlled environment in which to test the change.

I find myself sitting in your camp ;-)

 

[DLHDesign]

I find myself sitting in your camp ;-)

Not really the most experienced nor (clearly) the most informed, but at least we have good Smores.