Nitrate

[JonasRoman]

So, a common subject, still needed to discuss as its something that surround the coral 24/7 and of our concern.
We had a thread recently where I posted an article about the negative metabolic effects of hign temp and high (0.19 so not ao high) nitrate together, and also the opposite beneficial effect of ammonium.
The discussion is relevent, is nitrate a problem also in normal temp or just when coral is getting stressed?

Since decades we have struggled getting nitrate down and invented nitrate reactors, carbon source method (vodka method) etc. We see nitrate as a pollutant, as its a waste product of the nitrification and insufficiently denitrification. Denitrification is always more hard to get a good turnover as it need anareobic areas which is harder to get than aerobic surfaces ofcourse.

So I think most aquarist agree we do not ignore a raising nitrate. But, where is the limit and how much concern should it make? We have a lot of examples of tanks that look fine with high nitrate. That can be because of adaptation, some corals have died so you now have a selection , and some corals genetically are less sensitive to nitrate .

I found another study(they are refereing to the previous one), with a different design from the other we have discussed, where they have compared a corals metabolic response in high temp (30 gr) versus normal (26 gr) with and without increased nitrate, AND also compared to ONLY high temp.

The interesting finding in this study is:The coral did NOT respond badly to solely high temp 30, but when you added nitrate(0.56 ppm NO3) to that it responded badly: reduced photosynthesis efficiency, increased risk of thermal bleaching, and decreased bacterial diversity. This was already at nitrate levels we consider low. With even lower nitrate (0.15 mg/l) similar findings but not so severe. (That resembles the study from 2021). Note also that the stress symptoms developed already after 2 days with a culmen day 14. There was no PO4 limitations.

In the era of zeovite, we discussed ultra low nutrition, and many with me was against that. I am still that. BUT what we didnt understand at that era was that it was probably the low PO4 that was the issue, not the low nitrate. Some of us dosed nitrate as we where scared. I think that was a great misunderstanding as we didnt know better.
Today, I am afraid of low PO4, and high nitrate.

My own tank: PO4 AND NO3 is raising last months, a lot of fishes. I will introduce one more deni-block, but so far do not open the GFO box as long as I am below 0.1 in PO4.

This field has really developed, and when people say its ok with 25 ppm in nitrate I just wonder if they have something more substantial than just "I have seen tanks with that and it looks good". Its a very weak argument, and I will say those choose to ignore these interesting data, even if its not 100% proven, its hard to deny these beatiful studies.

https://www.sciencedirect.com/science/article/abs/pii/S0141113625001552


Jonas

 

[Garf]

30C is very warm for a tank. Don't have access to see if the negatives suddenly start at 30C or if they start lower, then ramp up. I expect if the negatives appear below 30C, they would have made a song and dance out of it.

 

[JonasRoman]

30C is very warm for a tank. Don't have access to see if the negatives suddenly start at 30C or if they start lower, then ramp up. I expect if the negatives appear below 30C, they would have made a song and dance out of it.

The test is 26 and 30. No ramp up. 30 degree with NO nitrate addition did not lead to negative responses. Thats interesting.

The scientists do this experiment as their hypothesis is that increased nitrate in ocean due to environmental changes may contribute to bleaching. The interesting differences from 2021 study I think is that they tested with only thermal stress aswell and found no neg effects until nitrate also was added.

 

[CHSUB]

You are going to have a hard time convincing this group no3 is better low than high, however continue your efforts. Most have not been around long enough to know any better. I have witnessed both ends of the scale. In the past many reefs suffered with high no3 using trickle type and undergravel filters. Then Sprung published a “better way” in his reef books. Imo, carbon dosing pushed no3 below natural levels and currently we are in a “push back” period.
I think at some point the hobby will rediscover no3 at 0.5 ppm is ideal, easily maintained, and still many times higher than natural levels. At that value the hobbyist will simply concentrate on more important parameters.

 

[JonasRoman]

You are going to have a hard time convincing this group no3 is better low than high, however continue your efforts. Most have not been around long enough to know any better. I have witnessed both ends of the scale. In the past many reefs suffered with high no3 using trickle type and undergravel filters. Then Sprung published a “better way” in his reef books. Imo, carbon dosing pushed no3 below natural levels and currently we are in a “push back” period.
I think at some point the hobby will rediscover no3 at 0.5 ppm is ideal, easily maintained, and still many times higher than natural levels. At that value the hobbyist will simply concentrate on more important parameters.

I am not interested in convincing anyone. The study is for all and interpretation are free, and speaks for itself
Yes, I believe same as you.

 

[Randy Holmes-Farley Verified Community Expert]

This field has really developed, and when people say its ok with 25 ppm in nitrate I just wonder if they have something more substantial than just "I have seen tanks with that and it looks good". Its a very weak argument, and I will say those choose to ignore these interesting data, even if its not 100% proven, its hard to deny these beatiful studies.

How is it weak to show real examples? Seems weaker to me to ignore real reef tanks and point to artificial scientific studies that show a stress to one or two species of coral from nitrate, and conclude its a problem for real reef tanks.

Maybe it is a stress, and maybe that stress is really not that important to a real reef tank at ordinary temperature, adequate phosphate, etc.

Example tanks with 100 ppm nitrate that anyone would be envious of seem extremely convincing to me. Richard Ross' tank with 1 ppm phosphate and 100 ppm phosphate, for example.


from it:

Randy’s Thoughts on Nutrient Target Ranges​

https://www.reef2reef.com/ams/randy’s-thoughts-on-nutrient-target-ranges.1087/


Figure 1. A very high nutrient system maintained by Richard Ross, with nitrate sometimes above 100 ppm and phosphate above 1 ppm. Details in this link:
https://www.reef2reef.com/threads/rich-ross-home-tank-guess-the-phosphate.296635/

 

[Randy Holmes-Farley Verified Community Expert]

You are going to have a hard time convincing this group no3 is better low than high, however continue your efforts. Most have not been around long enough to know any better. I have witnessed both ends of the scale. In the past many reefs suffered with high no3 using trickle type and undergravel filters. Then Sprung published a “better way” in his reef books. Imo, carbon dosing pushed no3 below natural levels and currently we are in a “push back” period.
I think at some point the hobby will rediscover no3 at 0.5 ppm is ideal, easily maintained, and still many times higher than natural levels. At that value the hobbyist will simply concentrate on more important parameters.

IMO, the issue is not only what is "best', but what exactly bad happens with higher than "optimal" nitrate.

If the answer is really little to nothing that an aquarist can observe in the tank, then this is just a nonissue.

So I'll turn it back to you and Jonas:

What observable problem (not a hypothetical stress problem) happens when average Joe keeps his reef tank with 50 ppm nitrate?

 

[JonasRoman]

How is it weak to show real examples? Seems weaker to me to ignore real reef tanks and point to artificial scientific studies that show a stress to one or two species of coral from nitrate, and conclude its a problem for real reef tanks.

Maybe it is a stress, and maybe that stress is really not that important to a real reef tank at ordinary temperature, adequate phosphate, etc.

I think you are right that its a stress, but the impact of that will ofcourse vary. I mean, the study says same, "nitrate only" did not cause any harm, it was together. But that says that if high nitrate we have loosen a security belt. With no security belt you can still drive the car without ending in a hospital if nothing more bad happens.

Also, from which perspective is the responsibility of evidense, that phalang that believes in unnatural levels is ok or that that believes in mimic natural levels? I think he proof of burden is more on the "nitrate group" than opposite to be honest.

 

[JonasRoman]

What observable problem (not a hypothetical stress problem) happens when average Joe keeps his reef tank with 50 ppm nitrate?

If not any other stress factors, maybe nothing (but we dont know as we dont know how the tank would look like if nitrate was lower, and we dont know if maybe some coral that died maybe would have survived, we only knows that those you see are ok), but if another stressfactor appears, we have lost a security belt. Why take the risk?? Turn around the question to you Randy:What is the bad thing with run this beatiful tank at nitrate 5 ish to be sure??