I'm dying on this hill - Phosphate is more important than alkalinity

[anth]

Im a bit envious of u guys with a po4 deficiency. I strive for 0.02-0.04 but i have a lot of fish and they seem to get thin if i adjust feeding to hit that po4 target. My nitrate never goes up or down (2.5ppm) unless i do a water change which i have only done once since october last year because of copper.
I would like to feed a lot more, can anyone advise on how i can increase the phosphate consumption of my tank to deal with the extra input.
550L of water
Maxspect duo skimmer
fuge reverse lit 11 hrs
40kg dry rock
Full triton method
I also installed rowaphos reactor today but i would rather not use this long term

 

[Lizbeli]

What a difference in your growth, nice job!

Many years ago when I set up my first tank I wanted to try out sps. I read everywhere to keep nutrients at 0. So as a newb, I started doing way more water changes and added gfo to reach those 0’s. My softies all shrunk and turned to nothing. Lps all suffered. And couldn't keep sps. I brought my phosphates down fast and hard. All while cutting my feeding in half. No bueno!

Definitely need to do a heavy import/export if you plan to run low nutrients like Perry said on the previous page (btw that tank is gorgeous). Today is much different. So many people are dosing nutrients into their systems.

Just crazy what we learn over the decades. Now in my newer system I have a good handful of acropora and have not had a single loss. I am however dealing with some algae after my refugium light literally burned. But it all gets fixed in time!

Happy reefing!

 

[Potatohead]

I don't want to run low nutrients really, like 5 and 0.1 would be ideal. My tank was at 5 nitrate for years but once I started dosing phosphate about six months ago it stayed there for a while but now over the last couple months it has now fallen back down. I'm not at all worried about it but obviously I don't want to bottom it out either.

It's possible now if I feed more I may be able to stop phosphate dosing, I will monitor it and make the necessary adjustments.

 

[Perry]

I don't want to run low nutrients really, like 5 and 0.1 would be ideal. My tank was at 5 nitrate for years but once I started dosing phosphate about six months ago it stayed there for a while but now over the last couple months it has now fallen back down. I'm not at all worried about it but obviously I don't want to bottom it out either.

It's possible now if I feed more I may be able to stop phosphate dosing, I will monitor it and make the necessary adjustments.

FWIW,
I added a sb reefbar actinic to the front of my t5 fixture and am already getting "pop" with several corals. Anecdotal, but I truly believe that tanks running t5 with heavier white emphasis fair much better in lower nutrients. Many years ago, when reading over user requirements for Zeovit program, they recommended running reef at 10k for optimal results. Why? Because ULNS run on Zeovit allowed for corals to glow under this spectrum. Fast forward to modern day reefing, forget 20k, that's considered running more whites with led. Even running all blue+ on t5 banks is still white in appearance compared to "most" led tanks. Just an observation, and something to factor in. I by no means suggest running ULNS on a tank full of frags, just too much on razors edge, but once they become mini-colony or larger, I feel you can then lower nutrients and begin with coral health and supplement programs to drive coloration. Again, with respect to running more white emphasis. Under mainly blue, colors look amazing. I aquire corals from my buddy's tank ran by led, the frags, when added to my tank don't pop, like they did in his tank, why? I run t5, at least until recently when I added a reefbar To each there own, but a mentor/reef buddy of mine always said. "If your corals aren't colorful under white lighting, then they aren't colorful " Biggles

 

[Potatohead]

I run six blue, an actinic and a purple. It sounds blue but it's really not that much, maybe 15k or so. The way things are going I'm not changing anything in regards to that. I've been meaning to add a blue strip for a long while but I just never have gotten around to it. Crazy blue pop for a couple hours a day just isn't my priority.

 

[Timfish]

Not surprised. Southampton did a series of experiements with various corals that had been maintained in an aquarium for a minumum of 2 years. Pretty much blew the notion of keeping phosphates low, < 0.03 mg/l, out of the water. Here's the links to the research:

Thier system setup

https://www.researchgate.net/public...he_susceptibility_of_reef_corals_to_bleaching
Fig 1 from the paper:

https://www.frontiersin.org/articles/10.3389/fmars.2015.00103/full

https://www.sciencedirect.com/science/article/pii/S0025326X17301601?via=ihub

 

[Diesel48]

Still targeting .1ppm phosphate? Still liking what you are seeing? I had some SPS frags that seemed to be doing well, encrusting on the plugs and such. However after about 3 weeks something changed and now they do not look so hot. Pretty frustrating. Tank is 18 months old now. Nitrate has been 10ish, phosphate between .03 - .04 on the Hana ULR For the past month. It was .06, seems like small difference but just trying to see better results than I am currently seeing. To many SPS frags have been lost.

 

[living_tribunal]

Not surprised. Southampton did a series of experiements with various corals that had been maintained in an aquarium for a minumum of 2 years. Pretty much blew the notion of keeping phosphates low, < 0.03 mg/l, out of the water. Here's the links to the research:

Thier system setup

https://www.researchgate.net/public...he_susceptibility_of_reef_corals_to_bleaching
Fig 1 from the paper:

https://www.frontiersin.org/articles/10.3389/fmars.2015.00103/full

https://www.sciencedirect.com/science/article/pii/S0025326X17301601?via=ihub

Been telling people this/referring them to the Rosset study for years. Corals will tolerate very low nitrate levels but they do not tolerate extremely low/non-existent phosphate levels. While corals need both N & P to survive, phosphate is more important. Translating that to maintaining a reef, if you want to limit nuisance algae, lower your N instead of zeroing your phosphates.

Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates

Enrichment of reef environments with dissolved inorganic nutrients is considered a major threat to the survival of corals living in symbiosis with dinoflagellates (Symbiodinium sp.). We argue, however, that the direct negative effects on the symbiosis ...

www.ncbi.nlm.nih.gov

 

[Potatohead]

Still targeting .1ppm phosphate? Still liking what you are seeing? I had some SPS frags that seemed to be doing well, encrusting on the plugs and such. However after about 3 weeks something changed and now they do not look so hot. Pretty frustrating. Tank is 18 months old now. Nitrate has been 10ish, phosphate between .03 - .04 on the Hana ULR For the past month. It was .06, seems like small difference but just trying to see better results than I am currently seeing. To many SPS frags have been lost.

Yes. I try and keep it around 0.12 or so. Any time it gets below about .08 I notice a difference in polyp extension and growth rate. Not in every coral, but in a few. I would much rather have it slightly high than low.

 

[Lovefish77]

Following. .very interesting topic.

 

[living_tribunal]

I will add one thing, as I was pretty passionate about this topic last year. There is a limit to reaping the growth benefits of elevated phosphate levels. I spent about 10 months progressively increasing phosphate levels while keeping N at a steady .5. I undoubtedly saw a dramatic increase in growth as the levels rose. The impact became noticeable at the .1-.15 mark. I continued to raise them all the way to .7. At this point, the corals were growing very fast but the few sps I keep did start to grow highly more porous skeletons. It got to the point where my wrasse would bump into a monti and it would break off.

Running high phosphate levels is great just don’t get out of control with it and be cautious if you primarily keep sps. Being moderate pays in this regard.

 

[anth]

For those of you that concentrate on the numbers so closely, is it an enjoyable part of the hobby for you? I'm genuinely curious because I hate testing and trying to tune into numbers but only because I find it boring. I leave my tank be and respond if something seems to not be well. I'm definitely not saying my way is better, it works for me and it's just how I enjoy the hobby. I see people post spread sheets and formulas and exact parameters and stress when they are .0X off and it makes me cringe because I wouldn't enjoy the hobby that way. So my question is for those of you that like to test frequently and keep exacting water results, do you do it because you enjoy that part of it or are you afraid the tank will fail if you don't do it that way?

I realise your post is months old but i am one of them. I love fine tuning and am often trying to find how different elements effect another eg po4, no3, alk. 3 weeks ago i raised my no3 to 25 ppm, my po4 is normally 0.018-0.06 after feeding. I have not noticed any difference im colour or growth from the raised no3 nor any problems elsewhere. My next goal is to raise po4 to 0.08-0.1 which i have tried before but ended up with gha and bryopsis.
Last time i did this by heavy feeding, so this time im thinking i might dose it instead. This way im not getting all the other extra nutrients to fuel the algae (thats my way of thinking anyway, feel free to correct me).

So anyway, thats the kind of thing that interests me about tweaking numbers, its kind of like a puzzle. And when you think about it (or at least when i think about it) this is how things progress. If you think about all the methods and the different approaches that have been seen in the reefing hobby throughout the years, it all boils down to experimentation and the obviously using nature as a guideline.

I consider myself a beginner and not some kind of guru but i love a good brain teaser. Other people may have other reasons for chasing numbers but this is mine.

thanks
Anth

 

[attilak]

A sudden decrease in phosphate is not good either. How many times have we heard about someone testing "too high," adding GFO and then having major issues.

I think stability is obviously number one, but I am rapidly forming the opinion that salinity, phosphate and alkalinity are the main talking points. The amount of sheer information online mentioning to keep a tank at .03 or so is huge, and frankly probably straight up wrong unless you are feeding five or six times a day.

Calcium, mag, nitrate also important, but the next level down.

Completely agree! my po4 was high and figured I try to reduce and did it too quick. All my bubble tip anenome's died off in a week.

 

[biophilia]

Really interesting thread!

Some food for thought:

- Hobby tests kits measure orthophosphate, and not other forms, so how much total phosphorus is actually present in a given aquarium is not often known. Probably a minor difference, but worth considering since bacterial action can convert organic phosphate back into inorganic form.

- The same goes for NO3: other forms of nitrogen available to corals and their symbionts like organic N (amino acids) and inorganic N as ammonium are usually not being factored in when talking about "N-P ratios".

- As @living_tribunal mentioned, elevated PO4 can result in increased tissue growth rates at the expense of the integrity of the animal's calcium carbonate skeleton and lead to more fragile corals. Increased growth and coloration aren't in themselves a proxy for determining overall coral health. Upping PO4 to encourage growth should probably be done carefully in tanks with lower alkalinity. Running at elevated alkalinity can help the skeletal growth keep up with the increased tissue growth.

- I'm not aware of any research looking at phosphate specifically, but there are some papers showing that elevated NO3 can either increase OR decrease growth rate in corals depending on the species. It would be really cool to see that Rosset et al. paper expanded on to corals other than Euphyllia paradivisa to see if species makes a difference in those ratios.

 

[LRT]

This is very interesting.
I cant speak to anything other than what ive seen on my mushroom garden over last year.
I've seen alk swing from 8-15
No3 swing from 0- off charts due to over dose.
Po4 0-.2
Salinity 1.023- 1.028
Temps 68-86f
Haven't lost one shroom yet and some only started growing and obtaining great color in higher Po4 and No3. Explosive color and growth actually.
My biggest problem ever came when I OD nitrates and bottomed out phosphates but fixed that dosing P and stabilizing N.

 

[Reef_Obsessed]

I just wanted to ask, because I’m too lazy to scroll through 8 pages or replies...what do you all dose for phosphates? I does Fourish Nitrogen for Nitrates.

 

[Alan Sunshine]

My phosphates are too hard high to be measured(Hanna) with nitrates at 5. All other parameters are rock stable. I feed once a day, run a refugium, GFO in a reactor, and do water changes every week. Phosphate E is on the way. Is this “old tank” syndrome? Am I still leaching out phosphates? Thoughts on management?

 

[Belgian Anthias]

Levels and availability?

In nature, nutrient levels are very low but the availability is very high.

If high nitrate and phosphate levels are measured on a bleaching reef, Is the bleaching a response on the high levels, or are the high levels the result of bleaching corals?

We do know levels do have very little effect on growth rates, availability does. unavailability kills.
5 or 10 ppm, growth rates are about the same, but it may last longer, depending on the limiting factor.
Growth is driven by the availability of all essential nutrients, not only nitrogen and phosphorus.
Why inorganic nutrients may build up in a well-lit aquarium and are not used up by photoautotrophs having an unlimited energy source?

Growth starts with the carbon source. The nitrogen source used is mainly responsible for growth rates, the use of nitrate slows down growth rates drastically. Micro -organisms prefer ammonia-nitrogen.
It is about water exchange rates and demand.
In their micro world growth means high demand. Microorganisms grow exponentially doubling their nutrient demand constantly. The level of inorganic nutrients in the water may be very high but this does not mean they are made available sufficiently. The level represents what is NOT used at the moment of measuring.

How the nitrate level may cause phosphorus starvation? Having nitrate does not mean it is used.
It has been shown one of the main causes of coral bleaching is caused by phosphorus starvation during periods of high demand supported by nitrogen availability; for example during periods with increasing temp. The use of nitrate slows down growth rates and demand, limiting the risk for phosphorus starvation.

High phosphorus availability supports ( increases) the calcification rates if enough CO3 is made available. The connection between phosphorus and alkalinity for coral growth?

Corals are heterotrophs! They use organic nutrients!

Inorganic nutrient levels of nitrate and phosphate are messengers, they are a guide for managing the system. They do NOT kill.
Ammonia does, nitrate does not.

Killing the messengers does not win wars.

High organic levels ( DOC) may kill corals.
Efficient remineralization keeps DOC very low.

The skimmer removes some of the building materials ( DOC) constantly and very selective, leaving inorganic nutrients and hydrophilic organics behind. Are these the building materials needed for closing the nutrient cycles?

What is the role of a skimmer in nitrogen and phosphorus management, in nutrient management in general?


Problems with nutrient levels? What will be the result of downrating the skim rate?

Nitrate is the end product of aerobic remineralization, of removing DOC. During remineralization most organic carbon is used for energy production and released as CO2, some are used for cell synthesis, for growth. When all organic carbon present is used up building materials are leftover to support ( photo-) autotrophic growth, to bring in organic carbon using CO2, to close the carbon cycle. Ammonia- nitrogen not used up during remineralization for growth, the nitrogen is safely stored in nitrate for later use, preventing ammonia to become toxic.

Nitrate supports anaerobic remineralization and the removal of constantly produced HS. ( denitrification + DNRA)
The main purpose of anaerobic remineralization is to keep biofilms healthy by constantly recycling biowaste in the absence of oxygen. Sulfate is used as an oxygen source.

Something must be the growth limiting factor! Managing a closed system is about finding the balance.

Managing nutrients starts by knowing how much may be removed, can be exported.

Restoring the nutrient balance can easily be done by managing growth and growth rates, growth on which we may have or obtain full control. For this, one can use a refuge, a biofilter.


Easy management is based on knowing what is going in and what is going out, about having a controllable, manageable export rate.

Adding only phosphates? or only nitrates? Why not? If one has a good reason.

 

[Bleigh]

I was telling @lostinreef a few days ago that I thought we were going to realized that higher PO4 levels are good. We were talking about how the testing equipment has gotten a lot more precise with lower margins of error. For all we know, when we have been running ultra low on the .01-.03, with margin of error, it may have been closer to .04-.07. Now that our margin of error has gone down, we may be starting to realize the true level of phosphates that gives better growth. Just my .02.

 

[living_tribunal]

Levels and availability?

In nature, nutrient levels are very low but the availability is very high.

If high nitrate and phosphate levels are measured on a bleaching reef, Is the bleaching a response on the high levels, or are the high levels the result of bleaching corals?

We do know levels do have very little effect on growth rates, availability does. unavailability kills.
5 or 10 ppm, growth rates are about the same, but it may last longer, depending on the limiting factor.
Growth is driven by the availability of all essential nutrients, not only nitrogen and phosphorus.
Why inorganic nutrients may build up in a well-lit aquarium and are not used up by photoautotrophs having an unlimited energy source?

Growth starts with the carbon source. The nitrogen source used is mainly responsible for growth rates, the use of nitrate slows down growth rates drastically. Micro -organisms prefer ammonia-nitrogen.
It is about water exchange rates and demand.
In their micro world growth means high demand. Microorganisms grow exponentially doubling their nutrient demand constantly. The level of inorganic nutrients in the water may be very high but this does not mean they are made available sufficiently. The level represents what is NOT used at the moment of measuring.

How the nitrate level may cause phosphorus starvation? Having nitrate does not mean it is used.
It has been shown one of the main causes of coral bleaching is caused by phosphorus starvation during periods of high demand supported by nitrogen availability; for example during periods with increasing temp. The use of nitrate slows down growth rates and demand, limiting the risk for phosphorus starvation.

High phosphorus availability supports ( increases) the calcification rates if enough CO3 is made available. The connection between phosphorus and alkalinity for coral growth?

Corals are heterotrophs! They use organic nutrients!

Inorganic nutrient levels of nitrate and phosphate are messengers, they are a guide for managing the system. They do NOT kill.
Ammonia does, nitrate does not.

Killing the messengers does not win wars.

High organic levels ( DOC) may kill corals.
Efficient remineralization keeps DOC very low.

The skimmer removes some of the building materials ( DOC) constantly and very selective, leaving inorganic nutrients and hydrophilic organics behind. Are these the building materials needed for closing the nutrient cycles?

What is the role of a skimmer in nitrogen and phosphorus management, in nutrient management in general?


Problems with nutrient levels? What will be the result of downrating the skim rate?

Nitrate is the end product of aerobic remineralization, of removing DOC. During remineralization most organic carbon is used for energy production and released as CO2, some are used for cell synthesis, for growth. When all organic carbon present is used up building materials are leftover to support ( photo-) autotrophic growth, to bring in organic carbon using CO2, to close the carbon cycle. Ammonia- nitrogen not used up during remineralization for growth, the nitrogen is safely stored in nitrate for later use, preventing ammonia to become toxic.

Nitrate supports anaerobic remineralization and the removal of constantly produced HS. ( denitrification + DNRA)
The main purpose of anaerobic remineralization is to keep biofilms healthy by constantly recycling biowaste in the absence of oxygen. Sulfate is used as an oxygen source.

Something must be the growth limiting factor! Managing a closed system is about finding the balance.

Managing nutrients starts by knowing how much may be removed, can be exported.

Restoring the nutrient balance can easily be done by managing growth and growth rates, growth on which we may have or obtain full control. For this, one can use a refuge, a biofilter.


Easy management is based on knowing what is going in and what is going out, about having a controllable, manageable export rate.

Adding only phosphates? or only nitrates? Why not? If one has a good reason.

The bleaching is not caused by elevated levels nitrate levels. Bleaching is an indirect externality when nitrate levels increase because, ceterus paribus, it’s a greater limiting factor to nuisance algae growth. When algae becomes the dominant consumer in the respective area, it then bottoms out the phosphate levels which then cause the bleaching of corals.

So the technical problem is phosphate deficiency, the cause is macro algae dominance, the catalyst is elevated N.

There is also research currently being done on if higher N levels themselves disrupt the symbiotic relationship between zoox and corals. The zoox converts very minor levels of N to the amino acids necessary for coral growth. Evidence suggests that elevated N levels cause issues with zooxanthelle in this process.