Nitrates and phosphates - what does the latest science say?

[tenurepro]

Hi all,
I just made this video discussing a recent meta-analysis of nutrient enrichment experiments.
This recent article by Shantz and Burkepile (Ecology 2014) reviewed over 50 studies on nutrient enrichment in reefs and found patterns that are in some cases opposite to the typical paradigm that nitrates and phosphates at detectable levels can inhibit coral growth.

https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/13-1407.1

What i took away from this study is that a lot of the typical recommendations for excessively controlling nitrates and phosphates were likely founded on a small number of biased studies that overemphasized negative effects of nutrient enrichment on corals.


Curious to here your thoughts!

 

[Potatohead]

I think "undetectable" ten+ years ago meant differently than today. Back then there wasn't enough resolution in test kits, now there is. So a test back then people though they had none when really there was a little bit. Like a Salifert phosphate test compared to the Hanna ULR, is basically worthless.

 

[CNDReef]

very Interesting. Definitely going against the “norm “ lol but I think there’s some truth to this. Let’s see what the experts say

 

[wesman42]

I think "undetectable" ten+ years ago meant differently than today. Back then there wasn't enough resolution in test kits, now there is. So a test back then people though they had none when really there was a little bit. Like a Salifert phosphate test compared to the Hanna ULR, is basically worthless.

I'm almost positive that 10 years ago titration testing for nutrients existed. I'm also positive mass spectrometers existed (which is what is used to ICP test your tank water).

What I don't think existed was Hanna checkers or the EASE of testing that there is today.

 

[Potatohead]

I'm almost positive that 10 years ago titration testing for nutrients existed. I'm also positive mass spectrometers existed (which is what is used to ICP test your tank water).

What I don't think existed was Hanna checkers or the EASE of testing that there is today.

Of course, but maybe the price point was out of touch for the average hobbyist until more recently.

I actually don't know, but did a Red Sea Pro nitrate kit exist ten years ago? It will test down under 1 ppm nitrate pretty easily. A Salifert kit won't. You can dilute the Salifert to get more resolution down low, but then you're deciphering between shades of light pink which makes it very difficult.

 

[reeferfoxx]

@tenurepro Loved the video! I'm happy to see another reefer grasping the concept and getting the information out. I'm a big fan of resolving tank issues with nutrients. Though, not always the case.

I don't think I need to defend anything Randy Holmes-Farley published however, even in his article it suggests elevated N and P can spur dinoflagellates. I'm only using dinos as any example for this particular point. Because, elevated N or P is only part of the equation. After looking at different dino species, we find they are specific to ocean regions, temps, and really just environmental impacts for those areas. My point is, some species can pop up with elevated N. Typically, this is without P or no measurable amount of P. That said, some tanks may not see dinos with elevated N with unmeasurable amounts of P. It might just be that that particular tank doesn't have a dinoflagellate from a region that would invade at those measurements. Also, other factors can impact or suppress growth like silicates or some trace element limitation.

In regards to nutrients for acropora, their symbionts are too another specie of dinoflagellate. As related above the limitation of either N or P does have an impact. With phosphorus some of us know that it binds to many other elements and most importantly, calcium carbonate. Calcium carbonate is what makes up the skeleton of stony coral. So, i think it's important to understand how beneficial it is to keep nutrients and to not let them get out of hand. Personally, high nutrients are perfectly fine as long as you have a strong CUC to counter any algae growth. Not to mention how beneficial bacteria utilizes nutrients as well. That another discussion.

 

[tenurepro]

While i agree that testing has improved; the main point [at least for me] that we can take away from the new paper is that the science that was used to justify the ULS paradigm seems to have shifted. That is, the old paradigm is not supported by science as much as we believed.

 

[Scrubber_steve]

Hi all,
I just made this video discussing a recent meta-analysis of nutrient enrichment experiments.
This recent article by Shantz and Burkepile (Ecology 2014) reviewed over 50 studies on nutrient enrichment in reefs and found patterns that are in some cases opposite to the typical paradigm that nitrates and phosphates at detectable levels can inhibit coral growth.

https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/13-1407.1

What i took away from this study is that a lot of the typical recommendations for excessively controlling nitrates and phosphates were likely founded on a small number of biased studies that overemphasized negative effects of nutrient enrichment on corals.


Curious to here your thoughts!

Hi tenurepro, nice video.
Some comments.
Peer review doesn't mean much in regards to accuracy of a paper's conclusions. Peer review basically just means a couple of un-named scientists, maybe or maybe not experienced in the same field as the author, have had a quick look through to check the methods used & conclusions put forward. Peer review doesn't attempt to replicate the experiment, nor necessarily delve deeply enough to refute the finer details in the methods used.
That is done by other scientists in the field providing follow-up papers, hopefully, completely independant of the original author.

You describe your tank as "dirty", ? I would disagree that NO3 at an average of 7.2, & PO4 at 0.2 is anywhere near approaching dirty. Perhaps to Zeovit - ultra low nutrient method advocates its dirty, but not to the average hobbiest.

Can you quote from the paper you provided on your video the actual readings for high levels of PO4 obtained in their experiment.

My tank once had NO3 at 60ppm plus, & po4 at 3.0ppm (unknown due to bad test kits). That is a dirty tank. Nothing would survive. I initially reduced both nutrients to zero (on home test kits) & things changes immediately, especially the proliferation of coralline algae, which of course is the most easily observed calcifying organism in an aquarium. Presently, my PO4 is 0.03 - permanently, & NO3 fluxuates between 0.25 & 8ppm.
Maintaining nutrients around these ranges is important but many other factors come into play, especially flow & light intensity - duration - spectrum.

cheers.

 

[reeferfoxx]

My tank once had NO3 at 60ppm plus, & po4 at 3.0ppm (unknown due to bad test kits). That is a dirty tank. Nothing would survive.

I agree with this too. It's my understanding that saturation in high levels of nutrients can foul the water mostly by decreasing overall oxygen.

 

[DudeBruh]

It’s truly amazing when returning to the hobby after 7 years how much can change.

 

[reeferfoxx]

#reefsquad #mods @Randy Holmes-Farley @Dana Riddle

Seeing if you guys would like to weigh in

 

[Brew12]

Hi all,
I just made this video discussing a recent meta-analysis of nutrient enrichment experiments.
This recent article by Shantz and Burkepile (Ecology 2014) reviewed over 50 studies on nutrient enrichment in reefs and found patterns that are in some cases opposite to the typical paradigm that nitrates and phosphates at detectable levels can inhibit coral growth.

https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/13-1407.1

What i took away from this study is that a lot of the typical recommendations for excessively controlling nitrates and phosphates were likely founded on a small number of biased studies that overemphasized negative effects of nutrient enrichment on corals.


Curious to here your thoughts!

First, let me say that I appreciate the work you put into this. It was well done.

I fall into the club who doesn't fear nutrients. I don't consider nitrates to be high until you hit 30ppm and don't consider them an issue until you get to higher levels than that. I do typically recommend PO4 to be kept below 0.1ppm but I would rather see 0.2 than 0.0.

I do want to offer a word of caution when it comes to these recent "high nutrient" studies. Recently a member posted links to a few of these studies which showed improved coral growth under phosphate enriched conditions. What did they call high phosphate? 0.03ppm.
So, if we are calling high nutrients 10ppm NO3 and 0.03ppm PO4 I agree, high nutrients are advantageous. When you start hitting 50ppm NO3 and 0.2ppm PO4 the results get much more mixed.

 

[Flippers4pups]

I for one agree with @tenurepro on these findings. I typically fun around 40ppm N03 and (as of late was P04 limited ,around 0.02) have been dosing 25ml of phosphate to bring it up. By doing so, I’m experiencing a unprecedented spike in growth and color. More growth than I’ve seen in a year. I’ve even stopped doing water changes thee weeks ago, but plan on a water change this coming weekend.

Nuisance algae is nonexistent in my system. No Dino’s, no diatoms, GHA...... nothing.

I have a minimal fish load population of just 5 fish in a 180 gallon total water volume system.
I do run a skimmer 24/7 and have a very large amount of chaeto growing in my refugium.

I do dose Kent Marine essential elements once a week at 15ml to replenish lost elements because of the lack of water changes.

All in all, this is working for me and my corals. Will this work for you? Don’t know.

One other thing, many well known hobbyists run “dirty” tanks. Sanjay, Richard Ross....... and more. They have spectacular systems full of healthy, colorful corals.

 

[Amoo]

good info in here. As somebody who's primary focus in this hobby are Nems, nutrients have always been a critical part of my systems. I've also been a long time believer in a Fuge, so you can double that. The levels I shoot for are generally around 5-10NO3 and .1 PO4

--

On a side note did the study somewhat contradict itself? Did it say that excess N would inhibit skeletal growth, but excess N would increase photosynthesis? So the coral has a weaker structure but healthier tissue?

 

[Brew12]

On a side note did the study somewhat contradict itself? Did it say that excess N would inhibit skeletal growth, but excess N would increase photosynthesis? So the coral has a weaker structure but healthier tissue?

I'm pretty sure this is an artifact of the way this study was done. It was a collection of other studies. What the referenced studies on skeletal growth may have called high nitrates may have been called low nitrates in the studies on photosynthesis.

 

[Amoo]

I'm pretty sure this is an artifact of the way this study was done. It was a collection of other studies. What the referenced studies on skeletal growth may have called high nitrates may have been called low nitrates in the studies on photosynthesis.

I don't have access to the study, but I would hope/assume that they mentioned somewhere if they went through the studies they were comparing to check to see what values were being used and categorized them based on that? I would hope it wasn't just like a yes/no check box without amplifying infos?

 

[Dana Riddle]

#reefsquad #mods @Randy Holmes-Farley @Dana Riddle

Seeing if you guys would like to weigh in

The coastal water along the island of Hawaii (and most likely other islands) have elevated nutrient levels for a couple of reasons. First, geologically-young lava rock leaches nitrates. In addition, nitrogen and phosphorus species are added by thousands of cesspools, septic tanks, boats' holding tanks and some wastewater treatment facilities. Corals were fine until the El Nino bleaching event of 2015. Those surviving corals are spawning and recovery should be complete in about a decade unless there is another major disruption.

 

[Flippers4pups]

Warning! Dana knows of Richards tank and how he reefs, at home, but here’s a video from Macna 2017.

Ladies and gentlemen, I give you......

Mr.Richard Ross and his way of reef keeping. His presentation does cover elevated nutrient levels, a little.

 

[Crashjack]

I kept tanks for 6-7 years from the mid-90’s through early 2000’s and never worried much about testing nitrates and phosphates, never dosed carbon, and my tanks looked great. Before I got back into the hobby about 14 months ago, I did a lot of research to “catch-up” on what I had missed or forgotten over the last 15 years or so. There was so much emphasis on maintaining low nutrients, I setup my new tank to be low-nutrient friendly. I even bought an extra dosing pump, assuming I would have to start dosing carbon 2-3 months in. After a while, I noticed I wasn’t getting much growth in my lps or zoas, or even coralline. The zoas also didn’t open very large, and even my chaeto stopped growing and was looking pale. The tank looked sterile... like the frags had been preserved instead of living and growing. I finally wound up with a bad case of dinos.

After following the advice to raise nitrates/phosphates from the long dinos thread, I noticed that my corals started spreading and growing, and the color was a lot better. I also saw that my zoas were opening up a lot bigger than they ever had. Coralline started growing and so was my chaeto. I’m not where tenurepro is as after I traded dinos for hair algae, I ignored nutrients for too long. The dinos came back but not as bad, and I addressed it a lot quicker. Even with the hair algae and 2nd round of dinos, my corals are still doing great, including my sps frags. I believe keeping nitrates/phosphates at decent levels might be as important as keeping ca/alk at proper levels. I don’t believe you can really set standard nutrient levels applicable to all tanks because you are always just measuring what hasn’t been taken-up by the life in the system. In other words, one could measure undetectable nutrients when in reality, considerable nutrients are being taken-up, or one could measure undetectable nutrients because there just aren’t any nutrients. Since you don’t really know what is being taken-up, keeping phosphate at maybe .05 ppm - .15 ppm and nitrate at maybe 5 - 15 ppm, probably insures that there are enough nutrients, but not so high as to cause other problems that can’t be addressed with a decent CUC.

 

[Lasse]

Thank you for the video

This is another tank that was running at PO4 levels around 1.5 - 2 and total unknown NO3 levels (probably very high - never measured at all). When I try to reduce the nutrients levels a little (and start to dose trace elements) I crashed the tank and it was put down in late 2015


My current tank run at PO4 levels between 0.04 - 0.1 and NO3 levels around 0.25 - 8. I dose both PO4 and NO3 on a daily basis


The reason why I construct my new tank in order to take away both PO4 and NO3 in an effective way - indeed so effective that I need to add both PO4 and NO3 was that I was concentrate around the nutrient flux. When I need to add these compounds - I have total control over this flux - the measurement of the water concentration is only tell me how much that is not consumed - if it raise - I add to much - if it decrease - I add to little. This will also mean that the levels will vary - but I think that this is exactly what´s happen in the wild with upwelling ad other similar events.

This is a very interesting article about this

https://www.nature.com/articles/d41586-018-05355-y

https://www.nature.com/articles/s41586-018-0202-3

Sincerely Lasse