The word on Phosphates

[mossanimal]

So I get conflicting information on phosphates. I get everything from that you have to have minimal numbers and that phosphates stunt coral growth or that it doesn't matter as long as it's stable and then recently I watched a video about a successful coral farmer that runs like 0.8 and Acro growing like crazy. Well, my 90 gallon classroom tank is about 5 months old with a 40 gallon sump with skimmer, chaeto refugium (chaeto growing like a weed) and separate deep mud mangrove display fuge. My Cephastrea and mushrooms are growing like crazy but very little growth of my zoas, GSP, Xenia and Toadstool. They are very beautiful and look great... just no growth. I realize the tank is young but I'm just wondering if I should try to get my phosphates down. Lately I've been getting less than 10 nitrates and 0.25ppm phosphates (both Salifert and API agree on this). The tank looks great (starting to get some coralline on back wall) and no serious algae problems other than some patches of very tough turf algae (see my other post). I have two clownfish and a blenny. So.... should I target getting those phosphates down and try to raise nitrates? Or... just be stable and wait?

 

[mossanimal]

I will add that I have strong flow with two small Jebao powerheads and a gyre (which might be too much... my Haddoni carpet anemone is having a hard time getting settled).

 

[randomfishdude]

Your tank is basically like mine. Exept I don't have Refugium and skimmer.
I would just recommend keeping them where they are.
My tank sits around .23 phos with 15 nitrate. I have acro that grows like crazy. But the xenia I have in the tank dosnt. Which is nice since I have another tank where the xenia is self fragging all over the tank.

So just keep things stable and coral will take off.

Also you sad it's a classroom tank as in you have that big of a tank in your classroom?

 

[rtparty]

Phosphate has been wrongly vilified for decades. Just keep things stable and consistent and the tank will find its balance and flourish

 

[mossanimal]

Your tank is basically like mine. Exept I don't have Refugium and skimmer.
I would just recommend keeping them where they are.
My tank sits around .23 phos with 15 nitrate. I have acro that grows like crazy. But the xenia I have in the tank dosnt. Which is nice since I have another tank where the xenia is self fragging all over the tank.

So just keep things stable and coral will take off.

Also you sad it's a classroom tank as in you have that big of a tank in your classroom?

Yeah! I use it as a focus for teaching ecosystems and marine biology to my 5-8 grade students. It's awesome.

 

[randomfishdude]

Yeah! I use it as a focus for teaching ecosystems and marine biology to my 5-8 grade students. It's awesome.

Dang ... lucky kids.
We didn't even get a marine biology class when I was in middle school.

my biology class our teacher never rememberd to finish setting up the 2 freshwater tanks she had. So they just kinda evaporated empty over the year.
At least we had a pretty cool snake!

 

[Timfish]

The reasons for corals to grow or not grow are very complex and include environmental conditions different from what they were used to and microbial issues in tank microbiomes as well as individual coral microbiomes. From what I've seen in others and my own systems it can take weeks to months and even years for a coral to acclimate and start growing.

Unfortunately the recommendation to keep PO4 low (in ppb) was espoused by "gurus" that didn't look at the research or what researchers were observing and it became the dogma still spouted by some. FWIW .03 mg/l is the threshold level to prevent phosphorus limitation in corals, identified by researchers at Southampton University in England using corals maintained in an aquarium for about a decade. .3 mg/l is what corals are subjected to with upwelling in the ocean. .5 mg/l might be acceptable for some as acros have been shown to increase growth up to this level. .9mg/l is the level the Steinhart Aqaurium's ex situ sexually reproduced acro colonies are being grwon out with. Rich Ross's (who's part of the team at Steinhart) has his acro dominate mixed reef sitting at 1.8 mg/l, his tank can be seen at the beginning of his MACNA presentation on phosphate. You can see his current levels as well as some cool videos of corals spawning in his thread.

ALso, what hasn't been pointed out until teh last few years is we are dealing with a lot more than just phosphate or Dissolved Inoragainc Pohsphorus or DIP. Reef systems have Particulate Organic Phosphorus or POP and Dissolved Organic Phosphorus or DOP, niether we can test for. As is evident in this figure from this paper on phosphorus cycling in corals it's possible depending on the foodwebs in a system corals may in fact be the source of phosphates as they process POP and DOP



If you're interested into looking into the microbial stuff here's some links:

"Coral Reefs in the Microbial Seas" This video compliments Rohwer's book of the same title (Paper back is ~$20, Kindle is ~$10), both deal with the conflicting roles of the different types of DOC in reef ecosystems. While there is overlap bewteen his book and the video both have information not covered by the other and together give a broader view of the complex relationships found in reef ecosystems

Changing Seas - Mysterious Microbes

Microbial view of Coral Decline

Nitrogen cycling in hte coral holobiont

BActeria and Sponges

Maintenance of Coral Reef Health (refferences at the end)

DNA Sequencing and the Reef Tank Microbiome

 

[mossanimal]

The reasons for corals to grow or not grow are very complex and include environmental conditions different from what they were used to and microbial issues in tank microbiomes as well as individual coral microbiomes. From what I've seen in others and my own systems it can take weeks to months and even years for a coral to acclimate and start growing.

Unfortunately the recommendation to keep PO4 low (in ppb) was espoused by "gurus" that didn't look at the research or what researchers were observing and it became the dogma still spouted by some. FWIW .03 mg/l is the threshold level to prevent phosphorus limitation in corals, identified by researchers at Southampton University in England using corals maintained in an aquarium for about a decade. .3 mg/l is what corals are subjected to with upwelling in the ocean. .5 mg/l might be acceptable for some as acros have been shown to increase growth up to this level. .9mg/l is the level the Steinhart Aqaurium's ex situ sexually reproduced acro colonies are being grwon out with. Rich Ross's (who's part of the team at Steinhart) has his acro dominate mixed reef sitting at 1.8 mg/l, his tank can be seen at the beginning of his MACNA presentation on phosphate. You can see his current levels as well as some cool videos of corals spawning in his thread.

ALso, what hasn't been pointed out until teh last few years is we are dealing with a lot more than just phosphate or Dissolved Inoragainc Pohsphorus or DIP. Reef systems have Particulate Organic Phosphorus or POP and Dissolved Organic Phosphorus or DOP, niether we can test for. As is evident in this figure from this paper on phosphorus cycling in corals it's possible depending on the foodwebs in a system corals may in fact be the source of phosphates as they process POP and DOP



If you're interested into looking into the microbial stuff here's some links:

"Coral Reefs in the Microbial Seas" This video compliments Rohwer's book of the same title (Paper back is ~$20, Kindle is ~$10), both deal with the conflicting roles of the different types of DOC in reef ecosystems. While there is overlap bewteen his book and the video both have information not covered by the other and together give a broader view of the complex relationships found in reef ecosystems

Changing Seas - Mysterious Microbes

Microbial view of Coral Decline

Nitrogen cycling in hte coral holobiont

BActeria and Sponges

Maintenance of Coral Reef Health (refferences at the end)

DNA Sequencing and the Reef Tank Microbiome

This is great. Very excited about this post!

 

[mossanimal]

Dang ... lucky kids.
We didn't even get a marine biology class when I was in middle school.

my biology class our teacher never rememberd to finish setting up the 2 freshwater tanks she had. So they just kinda evaporated empty over the year.
At least we had a pretty cool snake!

Well I'm an ex-marine scientist landlocked on Lake Superior and I miss the ocean. So I'm bringing it here. Teaching marine biology to middle schoolers is not normal in the Midwest.

 

[mossanimal]

The reasons for corals to grow or not grow are very complex and include environmental conditions different from what they were used to and microbial issues in tank microbiomes as well as individual coral microbiomes. From what I've seen in others and my own systems it can take weeks to months and even years for a coral to acclimate and start growing.

Unfortunately the recommendation to keep PO4 low (in ppb) was espoused by "gurus" that didn't look at the research or what researchers were observing and it became the dogma still spouted by some. FWIW .03 mg/l is the threshold level to prevent phosphorus limitation in corals, identified by researchers at Southampton University in England using corals maintained in an aquarium for about a decade. .3 mg/l is what corals are subjected to with upwelling in the ocean. .5 mg/l might be acceptable for some as acros have been shown to increase growth up to this level. .9mg/l is the level the Steinhart Aqaurium's ex situ sexually reproduced acro colonies are being grwon out with. Rich Ross's (who's part of the team at Steinhart) has his acro dominate mixed reef sitting at 1.8 mg/l, his tank can be seen at the beginning of his MACNA presentation on phosphate. You can see his current levels as well as some cool videos of corals spawning in his thread.

ALso, what hasn't been pointed out until teh last few years is we are dealing with a lot more than just phosphate or Dissolved Inoragainc Pohsphorus or DIP. Reef systems have Particulate Organic Phosphorus or POP and Dissolved Organic Phosphorus or DOP, niether we can test for. As is evident in this figure from this paper on phosphorus cycling in corals it's possible depending on the foodwebs in a system corals may in fact be the source of phosphates as they process POP and DOP



If you're interested into looking into the microbial stuff here's some links:

"Coral Reefs in the Microbial Seas" This video compliments Rohwer's book of the same title (Paper back is ~$20, Kindle is ~$10), both deal with the conflicting roles of the different types of DOC in reef ecosystems. While there is overlap bewteen his book and the video both have information not covered by the other and together give a broader view of the complex relationships found in reef ecosystems

Changing Seas - Mysterious Microbes

Microbial view of Coral Decline

Nitrogen cycling in hte coral holobiont

BActeria and Sponges

Maintenance of Coral Reef Health (refferences at the end)

DNA Sequencing and the Reef Tank Microbiome

So I’m starting to go through these videos and one question just came to me. The idea of algae releasing DOC is new to me. I’m assuming this is a waste product? But it made me wonder about the huge ball of chaeto that I have in my refugium and if the DOC it produces is enough to play a role in my tank. I also have what is essentially an algal scrubber in my mangrove fuge because my propagules still have the styrofoam supporting them while they take root. That styrofoam hosts an amazing algal turf that I have to remove every couple of days. Anyway… just got me to thinking…

 

[Randy Holmes-Farley Verified Community Expert]

Unfortunately the recommendation to keep PO4 low (in ppb) was espoused by "gurus" that didn't look at the research or what researchers were observing and it became the dogma still spouted by some.

Wow, that is both harsh and incorrect,IMO. It makes us sound ignorant and uninformed.

When I wrote an article on calcification in 2002, I referenced papers at the time that showed elevated phosphate inhibited calcification. I do not recall seeing any others at that time which refuted the notion, and most of us assumed that natural levels of phosphate was a good goal.

These are from that 2002 article:

1. Effects of elevated nitrogen and phosphorus on coral reef growth.Kinsey, Donald W.; Davies, Peter J. Limnol. Oceanogr. (1979), 24(5), 935-40.
2. ENCORE: the effect of nutrient enrichment on coral reefs. Synthesis of results and conclusions Dennison, W.; Erdmann, M.; Harrison, P.; Hoegh-Guldberg, O.; Hutchings, P.; Jones, G. B.; Larkum, A. W. D.; O’Neil, J.; Steven, A.; Tentori, E.; Ward, S.; Williamson, J.; Yellowlees, D. Marine Pollution Bulletin (2001), 42(2), 91-120.

Aquarium Chemistry: The Chemical and Biochemical Mechanisms of Calcification

All reef aquarists are versed in the fact that such organisms remove calcium and carbonate from the water column in order to provide materials for calcification. Exactly how calcification takes place, however, is rarely considered.

reefs.com

 

[Randy Holmes-Farley Verified Community Expert]

This is great. Very excited about this post!

It is a biased and incorrect accounting of history, IMO.

 

[jason2459]

Rich Ross's (who's part of the team at Steinhart) has his acro dominate mixed reef sitting at 1.8 mg/l,

He runs lower then that right now and can see the correct values on this page here along with where he's at with Alkalinity as well now.

Rich Ross - Home Tank - guess the phosphate

Are you planning to go lower or is the mid .65 where you want to be? Only reason I'm asking because I doubt the reduction you made really matters much one way or the other. I have an easy way of testing so as long as it is easy I am interested in messing with it, and looking for post feeding...

www.reef2reef.com

 

[Randy Holmes-Farley Verified Community Expert]

ALso, what hasn't been pointed out until teh last few years is we are dealing with a lot more than just phosphate or Dissolved Inoragainc Pohsphorus or DIP. Reef systems have Particulate Organic Phosphorus or POP and Dissolved Organic Phosphorus or DOP, niether we can test for. As is evident in this figure from this paper on phosphorus cycling in corals it's possible depending on the foodwebs in a system corals may in fact be the source of phosphates as they process POP and DOP

Not been pointed out? I have discussed it many times since 2000.

Organic Compounds in the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com

AquariumFish.com :: Aquarium Fish International :: The monthly magazine for both novice and expert aquarium hobbyists.

Organic Phosphates​

Unfortunately for reef keepers, the world of organic phosphorus compounds is far more complex than inorganic phosphates. Many common biochemicals contain phosphate esters. Every living cell contains some. Molecules such as DNA, ATP, phospholipids (lecithin), and many proteins contain phosphate groups. In these molecules, the basic phosphate structure is covalently attached to the remainder of the organic molecule through one or more phosphate ester bonds to a carbon atom.

These bonds are stable for some period of time in water, but will eventually break down to release inorganic orthophosphate from the organic part of the molecule, a process that can be sped up through the action of enzymes in a reef tank. Many of these organic phosphate compounds will be readily removed from a tank by skimming. Export of organic phosphates is the major way that skimming can result in reduced inorganic orthophosphate levels in a tank. Orthophosphate ions themselves are not significantly removed via skimmate (since they do not adsorb onto an air/water interface), but organic phosphates can be removed before they are converted into inorganic orthophosphate.

An important point about organic phosphates is that they will mostly not be impacted by phosphate-binding materials sold to the aquarium hobby. Consequently, while these products may do a fine job of reducing inorganic orthophosphate, they may not help an algae problem that is caused primarily by organic phosphates.

A final point is that organic phosphates will not be detected by most test kits. Those that do detect organic phosphates (e.g., Hach PO-24) break the phosphate off of the organic compound and thereby convert it into inorganic orthophosphate prior to testing. However, these kits are tedious and expensive, and not for every hobbyist.

Chemistry And The Aquarium: Phosphorus: Algae’s Best Friend

This article describes some of the issues around phosphorus in reef tanks, including the forms that it takes, its origins, ways to test for it, and most importantly, ways to export it.

reefs.com

 

[Thales]

He runs lower then that and can see the correct values on this page here along with where he's at with Alkalinity as well now.

Rich Ross - Home Tank - guess the phosphate

Are you planning to go lower or is the mid .65 where you want to be? Only reason I'm asking because I doubt the reduction you made really matters much one way or the other. I have an easy way of testing so as long as it is easy I am interested in messing with it, and looking for post feeding...

www.reef2reef.com

I was running it that high when I did that talk and for a couple years around there (2014ish). I brought them down to see if I saw any difference and I didn't. Then I ignored it for a while and they went back up. Then I started dosing lanth into the skimmer a low rates to see how that worked and kind of left it alone. It was under .2 for a while. Then I stopped caring again and it went up above 1.0. Then I got a new way to easily test phosphate so I started playing with it again, and it is down to around .5.
After the AWC got established, the nitrate came down, but not the po4.

 

[MrGisonni]

dang!! @Randy Holmes-Farley brought his receipts! Lol.
Fellow marine science teacher here. This is what I strive for from Randy's advice. I do however keep my nitrates a bit higher, 15-20 so they don't bottom out. It's a balancing act for me. Phosphates go up too much, I use a tiny bit of rowaphos. If they go low, I feed reef roids.

 

[mossanimal]

It is a biased and incorrect accounting of history, IMO.

My ears are open! My background is in marine science and aquatic biology even though I've been out of it for a while. Most of my work was on the monitoring end and taxonomy rather than chemistry... but I'm now fired up to delve a bit more into the primary research. I was very happy that he posted those videos on DOM.... that was eye opening.

 

[MrGisonni]

My ears are open! My background is in marine science and aquatic biology even though I've been out of it for a while. Most of my work was on the monitoring end and taxonomy rather than chemistry... but I'm now fired up to delve a bit more into the primary research. I was very happy that he posted those videos on DOM.... that was eye opening.

Marine Affairs (Environmental Science and Policy) UM. I have been teaching highschool marine science for 28 years. Chemistry is not in my wheelhouse so I take the advice of others, tinker a bit, make my observations, and find the sweet spot in my mixed reef. Follow the scientific method my friend

 

[Randy Holmes-Farley Verified Community Expert]

My ears are open! My background is in marine science and aquatic biology even though I've been out of it for a while. Most of my work was on the monitoring end and taxonomy rather than chemistry... but I'm now fired up to delve a bit more into the primary research. I was very happy that he posted those videos on DOM.... that was eye opening.

Here’s my nutshell opinion on phosphate;

1. Corals in the ocean thrive at inorganic phosphate levels undetectable by most kits.

2. Corals in many reef tanks do not thrive at those low levels, but do thrive in many tanks if the inorganic phosphate levels are raised.

3. The disconnect between 1 and 2, which confounded reefers for a long time, is likely explained by greater levels of particulate feeding in the ocean. ULNS systems in reef tanks thrive when given more particulate and possibly dissolved organic foods.

4. Algae is spurred by elevated phosphate, making #2 challenging unless there are a lot of herbivores or other ways algae is deterred.

5. I still think it is very possible that elevated inorganic phosphate may deter coral calcification, and possibly coralline algae as well, as some studies have suggested, but that does not mean corals, or at least some/many corals cannot still thrive. One does not need the fastest growth rates to thrive.

6. Some tanks will naturally have sufficient particulate and dissolved organic P to allow corals to get enough P at very low inorganic phosphate levels. Growing bacteria is one potential way to achieve this.

Taken together, these are the basis for my recommendation that a good range is 0.03 to 0.1 ppm phosphate, with values above that range better than below it, with the exception of cases where sufficient particulate food is added. I usually leave off that last section because I consider particulate feeding an advanced reef topic that does not always translate well for beginners.

 

[jda]

To add on, this can get tricky since some corals will not care about elevated residual po4 and some will care a lot. Generalizing about "corals," or "SPS" or whatever is not helpful. I mostly have acropora in my tank and there are some that will suffer, stop growing and die back at .1, or so, where others can go to 1.0 and beyond.

I measure about 1-3 (sometimes up to 5 on occasion) ppb on Hannah Ultra low Phosphorous checker. When I had a Hach Total P kit which tests all kinds of phosphates and phosphorous sources, not just orthophosphate, the numbers were 5-10x higher than this. These other forms get phosphorous to your corals too.

Just testing po4 does not tell you the whole story and can be fools gold, IMO. All that it tells you for sure is that you have a surplus.

I, for one, see MUCH faster coralline growth with lower no3 and po4 levels... much faster. Chaeto grows faster for me too, but it will still grow in higher level tanks. I do not experience true acropora burnt tips because 1-3ppb of po4 and .1 no3 are not Ultra Low... just ocean type of level - if you get below these, usually needing chemicals and media, then the skeletons can calcify so fast that they can outgrow organic tissue.

Feed your fish a lot, export a lot. Keep residual levels fairly low if you want to keep any coral at any time, or choose corals that thrive in the levels that you want to keep - find your zen place for cost/effort of export. The rest will be OK.