Shouldn't we mimic nature also concerning alkalinity?

[Fish Fan]

I would say that it's best to be slightly above 7 and not too much higher. Thanks to my own devices, like Alkatronic, I have monitored and done thousands of KH measurements with just a few hours between, since 8 years back. This is not a scientific observation, just an observation, but in my systems, I am confident that I can see a healthier tank overall when I'm more close to 7.

The problem with running Alk at 7 dKH for most people is going to be the testing. Most home, hobby-level test kits have a margin of error, and if your test kit is reading slightly high, and you're measuring 7 dKH, you're actually a little lower than natural seawater. For that reason, I like the 8 to 9 Alk range, which I believe gives some leeway to allow for test kit error.

I also agree that running a super high Alk and pH is best for those growing corals professionally or competitively.

 

[rtparty]

For years I’ve run and promoted alkalinity below 8dkh because I’ve always had the healthiest corals, especially SPS, when running alkalinity closer to ocean levels.

I don’t need any scientific proof to try and convince myself or others. The tanks I want to emulate run lower alkalinity. That’s all I need to see and know.

 

[BeanAnimal]

You can turn that around aswell: supranormal kh and pH drive the skeleton formation to a speed that soft tissue formation can not catch up. Meaning fast growth is not always same as healthy coral.

You can turn anything around, but what does it mean. There is no single definition of "healthy," which is the point. Optimal or best is also not defined. Is it a coral that can be plopped back in the ocean and survive, indistinguishable from its parent colony? One that withstands your powerhead, but not real tidal currents? One adapted to your photoperiod, or the sun's?

Why are we assuming that what happens in "nature" is optimal, other than in nature?

What is optimal is what meets our individual goals: growth, color, durability, or hardiness in the new environment. The original "natural" environment is no longer connected. A pepper plant in Texas is a perennial fruit producing shrub. In Pennsylvania it's an annual. Bring it indoors for winter under synthetic light and fertilizer, and does it matter which environment was its "natural" origin or that those inputs match it?

 

[areefer01]

I recall this came up many years ago elsewhere with faster growth rate vs rapid calcification vs coral health.

Measurement	Fiji (December 13, 2024)
Salinity (PSU)	35.33
Carbonate hardness (dKH)	6.85
Chloride (mg/l)	19941
Sodium (mg/l)	11117
Magnesium (mg/l)	1323
Sulfur (mg/l)	921.3
Calcium (mg/l)	417.4
Potassium (mg/l)	415.2
Bromine (mg/l)	67.87
Strontium (mg/l)	8.03
Boron (mg/l)	4.54
Fluorine (mg/l)	1.04
Lithium (µg/l)	189.7
Silicon (µg/l)	56.03
Iodine (µg/l)	78.71
Barium (µg/l)	2.93
Molybdenum (µg/l)	10.37
Nickel (µg/l)	Normal (near nature)
Manganese (µg/l)	Below normal
Arsenic (µg/l)	Normal (near nature)
Beryllium (µg/l)	Normal (near nature)
Chrome (µg/l)	Normal (near nature)
Cobalt (µg/l)	Normal (near nature)
Iron (µg/l)	Below normal
Copper (µg/l)	Normal (near nature)
Selenium (µg/l)	Normal (near nature)
Silver (µg/l)	Normal (near nature)
Vanadium (µg/l)	1.39
Zinc (µg/l)	Critically low
Tin (µg/l)	0.55
Nitrate (mg/l)	Below normal
Phosphorus (µg/l)	6.67
Phosphate (mg/l)	0.02
Aluminium (µg/l)	Normal (near nature)
Antimony (µg/l)	Normal (near nature)
Bismuth (µg/l)	Normal (near nature)
Lead (µg/l)	Normal (near nature)
Cadmium (µg/l)	Normal (near nature)
Lanthanum (µg/l)	Normal (near nature)
Thallium (µg/l)	Normal (near nature)
Titanium (µg/l)	Normal (near nature)
Tungsten (µg/l)	Normal (near nature)
Mercury (µg/l)	Normal (near nature)

 

[KrisReef]

I recall this came up many years ago elsewhere with faster growth rate vs rapid calcification vs coral health.

Measurement	Fiji (December 13, 2024)
Salinity (PSU)	35.33
Carbonate hardness (dKH)	6.85
Chloride (mg/l)	19941
Sodium (mg/l)	11117
Magnesium (mg/l)	1323
Sulfur (mg/l)	921.3
Calcium (mg/l)	417.4
Potassium (mg/l)	415.2
Bromine (mg/l)	67.87
Strontium (mg/l)	8.03
Boron (mg/l)	4.54
Fluorine (mg/l)	1.04
Lithium (µg/l)	189.7
Silicon (µg/l)	56.03
Iodine (µg/l)	78.71
Barium (µg/l)	2.93
Molybdenum (µg/l)	10.37
Nickel (µg/l)	Normal (near nature)
Manganese (µg/l)	Below normal
Arsenic (µg/l)	Normal (near nature)
Beryllium (µg/l)	Normal (near nature)
Chrome (µg/l)	Normal (near nature)
Cobalt (µg/l)	Normal (near nature)
Iron (µg/l)	Below normal
Copper (µg/l)	Normal (near nature)
Selenium (µg/l)	Normal (near nature)
Silver (µg/l)	Normal (near nature)
Vanadium (µg/l)	1.39
Zinc (µg/l)	Critically low
Tin (µg/l)	0.55
Nitrate (mg/l)	Below normal
Phosphorus (µg/l)	6.67
Phosphate (mg/l)	0.02
Aluminium (µg/l)	Normal (near nature)
Antimony (µg/l)	Normal (near nature)
Bismuth (µg/l)	Normal (near nature)
Lead (µg/l)	Normal (near nature)
Cadmium (µg/l)	Normal (near nature)
Lanthanum (µg/l)	Normal (near nature)
Thallium (µg/l)	Normal (near nature)
Titanium (µg/l)	Normal (near nature)
Tungsten (µg/l)	Normal (near nature)
Mercury (µg/l)	Normal (near nature)

I’m wondering where in the reef in Fiji was this sample collected?

I wonder what we could find if we collected oceanic water upstream from a reef, on the reef itself, and then downstream (down current really) /

Would we be able to detect what was in the water upstream, and what was removed by the reef(Bio uptake-presumably), looking at the difference(s)

This data set had low nitrate and iron, (and other factors that I am glossing over) , both are useful for growth in marine systems, and low alkalinity, this from bio-activity or is it “The Optimal level “ for a reef, and presumably for a reef tank also?

I love that someone has measured it, but wonder about the upstream/ downstream numbers, if they are available?

 

[areefer01]

I’m wondering where in the reef in Fiji was this sample collected?

I wonder what we could find if we collected oceanic water upstream from a reef, on the reef itself, and then downstream (down current really) /

Would we be able to detect what was in the water upstream, and what was removed by the reef(Bio uptake-presumably), looking at the difference(s)

This data set had low nitrate and iron, (and other factors that I am glossing over) , both are useful for growth in marine systems, and low alkalinity, this from bio-activity or is it “The Optimal level “ for a reef, and presumably for a reef tank also?

I love that someone has measured it, but wonder about the upstream/ downstream numbers, if they are available?

I collected this sample during my safety stop on the last day of diving. One of the south west dive sites from the main island. 15 - 20 feet with a max temp of 81 F. There is nothing scientific or professional on the collection. I had a spare ICP test laying around so tossed it in the dive bag. Shot ATI a message asking if they are ok with me sending in a sample of NSW and they said it was fine. They also noted that for best results keep the sample time to their lab within 14 days.

Current was strong during this safety stop so I was darting below the reef while staying within my stop parameters and air. Max depth on this dive was 71 feet. Average was 37 feet. Basically circling around this reef crest from bottom to top. There is another one behind me so we did sort of a figure 8.

Not a great picture but you get an idea of what the area looked like. Lots of Anthias, Damsels, darting in between the Acropora. The interesting thing is that as you are closer to the reef structure then you start to see the smaller angelfish like the Coral Beauty or Lemon Peels working through the structure and the tangs. Anthias and Damsels are feeding over the top while managing the harems.

Long story short this is just for fun because I could.

 

[KrisReef]

I collected this sample during my safety stop on the last day of diving. One of the south west dive sites from the main island. 15 - 20 feet with a max temp of 81 F. There is nothing scientific or professional on the collection. I had a spare ICP test laying around so tossed it in the dive bag. Shot ATI a message asking if they are ok with me sending in a sample of NSW and they said it was fine. They also noted that for best results keep the sample time to their lab within 14 days.

Current was strong during this safety stop so I was darting below the reef while staying within my stop parameters and air. Max depth on this dive was 71 feet. Average was 37 feet. Basically circling around this reef crest from bottom to top. There is another one behind me so we did sort of a figure 8.

Not a great picture but you get an idea of what the area looked like. Lots of Anthias, Damsels, darting in between the Acropora. The interesting thing is that as you are closer to the reef structure then you start to see the smaller angelfish like the Coral Beauty or Lemon Peels working through the structure and the tangs. Anthias and Damsels are feeding over the top while managing the harems.

Long story short this is just for fun because I could.

Thanks for grabbing and submitting the sample, and for the other information about the situation.

I wish we were doing a dive there, right now! Great image, btw. Thanks again for the data point. There certainly is plenty of healthy coral in that place.

 

[mcarroll]

For one reference: http://dx.doi.org/10.1029/2011JC007603
...alkalinity consumption over the reef as well as many other forces are influencing the alk level (and availability) across the reef.

Also, corals probably exert more control over their internal chemistry (and far more easily) than is generally presumed.

I do like "emulate nature" as a general axiom for problem solving in reefing.

 

[JonasRoman]

You can turn anything around, but what does it mean. There is no single definition of "healthy," which is the point. Optimal or best is also not defined. Is it a coral that can be plopped back in the ocean and survive, indistinguishable from its parent colony? One that withstands your powerhead, but not real tidal currents? One adapted to your photoperiod, or the sun's?

Why are we assuming that what happens in "nature" is optimal, other than in nature?

What is optimal is what meets our individual goals: growth, color, durability, or hardiness in the new environment. The original "natural" environment is no longer connected. A pepper plant in Texas is a perennial fruit producing shrub. In Pennsylvania it's an annual. Bring it indoors for winter under synthetic light and fertilizer, and does it matter which environment was its "natural" origin or that those inputs match it?

I disagree. First, you can't turn "everything" around. At least not if you ment to be serious. My comment to Randy was based on some studies that too fast coral growth is unhealthy for the coral.
Also, healthy coral is ofcourse not that difficult to define as you say. I think we all know what a healthy coral is. Like it's easy for a doctor to say if a human is not sick an experienced can tell same for a marine specimen.
We know that stability is important and subject here is to discuss if supra high alkalinity really is that good as some say.
There are actually studies telling us that skeleton for instance is,more fragile of grow too fast.


Jonas

 

[JonasRoman]

For years I’ve run and promoted alkalinity below 8dkh because I’ve always had the healthiest corals, especially SPS, when running alkalinity closer to ocean levels.

I don’t need any scientific proof to try and convince myself or others. The tanks I want to emulate run lower alkalinity. That’s all I need to see and know.

Think you are right, and actually you have convinced yourself

 

[Lasse]

For one reference: http://dx.doi.org/10.1029/2011JC007603
...alkalinity consumption over the reef as well as many other forces are influencing the alk level (and availability) across the reef.

Also, corals probably exert more control over their internal chemistry (and far more easily) than is generally presumed.

I do like "emulate nature" as a general axiom for problem solving in reefing.

Thank you for this article - at least it will help not scare the crap out of aquarists when they read 6.5 in dKH. Scientific articles have the disadvantage that they measure things differently from us aquarists so the numbers given here cannot be interpreted by most people. Below I have made an attempt to convert the scientific measure µeq/Kg to the measurement value most used by us - dKH. We know that 1 meq is 2.8 dKH so 1000 µeq is then 2.8 dKH. Now they have measured µeq/Kg and the dKH concept refers to per liter even though it is unsorted. I have therefore multiplied the given value by 1.0233. My formula = (µeq/Kg /1000)*1,0233*2,8. Correct me if I´m wrong.

This graph below show the total alkalinity in 3 different sample points at the reef flat nearest the most important influx channel - See this . There is no Ta figures for the incoming water but its possible to calculate a average figure for it

This graph show the delta total alkalinity in dKH compared with incoming water. See this. S1 value calculated.

Because I dose alkalinity during night time - my dKH vary between around 7 and 8.3 during a day

Sincerely Lasse

 

[Randy Holmes-Farley Verified Community Expert]

On a related note, the first 15-20 minutes or so of my next live stream (Tuesday, Aug 25, 7 pm ET) will discuss the mechanism that corals used to deposit skeletons, which largely explains why higher alk and higher pH boost the calcification rate. It also explains why other ions (say, uranium or strontium) get incorporated.

The remainder of that live stream will be Q and A supplied via the live chat.

Hope to see you there!

 

[EnterName]

On a related note, the first 15-20 minutes or so of my next live stream (Tuesday, Aug 25, 7 pm ET) will discuss the mechanism that corals used to deposit skeletons, which largely explains why higher alk and higher pH boost the calcification rate. It also explains why other ions (say, uranium or strontium) get incorporated.

The remainder of that live stream will be Q and A supplied via the live chat.

Hope to see you there!

I'm afraid 7pm ET will be 1am here so I'm not sure I can make it but will certainly watch it.

I just stumbled upon an article when I was thinking about dosing Sr to reach natural levels again. It's about Strontianite in coral skeleton which apparently shouldn't be there if strontium was just taken up through the calcium pathway by accident.
Unfortunately it's behind a paywall so I will have to check if I can get my hands on it: https://pubmed.ncbi.nlm.nih.gov/9072808/

It doesn't prove that corals need Strontium but it would indicate that the uptake mechanism is quite complex and maybe more than accidental, I'm excited to learn a bit about it, sounds like a very interesting topic

Thank your for doing these streams I really enjoyed the last one and the birthday stream.

 

[BeanAnimal]

I disagree. First, you can't turn "everything" around. At least not if you ment to be serious. My comment to Randy was based on some studies that too fast coral growth is unhealthy for the coral.
Also, healthy coral is ofcourse not that difficult to define as you say. I think we all know what a healthy coral is. Like it's easy for a doctor to say if a human is not sick an experienced can tell same for a marine specimen.
We know that stability is important and subject here is to discuss if supra high alkalinity really is that good as some say.
There are actually studies telling us that skeleton for instance is,more fragile of grow too fast.


Jonas

I was serious, you used the "turn around" as a pivot away from the point that Randy made. One can turn any argument around to avoid an answer to what was directly said.

I said "healthy," "optimal," and "natural" are undefined and depend on the goal, outside the native environment. Your "goal" is to mimic the native environment, which already assumes the coral is best in the native environment. That's circular, it's only "best" if the goal is "just like the native environment," and that's the thing you haven't argued for, you are assuming it. I gave specific examples to show the fallacy. You didn't address any of them and circled back to health.

Being able to spot gross coral health by eye is a broad observation. Claiming a specific dKH causes better health is a narrow claim. You're using the broad observation to stand in for the narrow claim. One doesn't prove the other. The claim rests in the circular fallacy outlined above.

You made the argument that fast growth makes the skeleton fragile, and fragile means unhealthy. That's your opinion that skeletal strength is a metric that defines health , an assumption, not a given. Your lower dKH argument (slower growth = strong) rests on that assumption, which rests on the two above. It is a circular set of arguments.

 

[Randy Holmes-Farley Verified Community Expert]

I'm afraid 7pm ET will be 1am here so I'm not sure I can make it but will certainly watch it.

I just stumbled upon an article when I was thinking about dosing Sr to reach natural levels again. It's about Strontianite in coral skeleton which apparently shouldn't be there if strontium was just taken up through the calcium pathway by accident.
Unfortunately it's behind a paywall so I will have to check if I can get my hands on it: https://pubmed.ncbi.nlm.nih.gov/9072808/

It doesn't prove that corals need Strontium but it would indicate that the uptake mechanism is quite complex and maybe more than accidental, I'm excited to learn a bit about it, sounds like a very interesting topic

Thank your for doing these streams I really enjoyed the last one and the birthday stream.

That is for the link. I believe the mechanisms (yes, a single coral appears to use two different mechanisms) that I’ll discuss can explain it as accidental, but, of course, such a possibility cannot exclude that it is intentional/needed. :)

 

[JonasRoman]

I would test it but after changing tanks I have to add new sand in small batches to keep phosphate from bottoming out. This keeps introducing more and more silicates which cause diatom stains that could skew the results.

From what I have observed so far is that the dinoflagellate genus changes. First Prorocentrum (I don't know if this was high or low DOC during that time), then Ostreopsis during "high" DOC and now Amphidinium during low DOC. However, I've not yet made a precise Triton N-DOC test or so and can only tell you that those DOC levels are high/low relative to each other. I have no way to translate them to ppm or similar units right now.

I'm still working on something Dan was interested in with regards to the UV275 TOC meters so I will make a Triton N-DOC test asap, but the last time I checked their N-DOC system was broken

Oh, I see. Concerning DOC we maybe have not knowledge yet what is high or low, or the "ref value" when we get issues. Triton have a lot of data but those are not connected to the "clinique". My believe (and if i remember correct there was an article about that), that its good to have low DOC for the overall health of the ecosystem.

 

[JonasRoman]

I was serious, you used the "turn around" as a pivot away from the point that Randy made. One can turn any argument around to avoid an answer to what was directly said.

I said "healthy," "optimal," and "natural" are undefined and depend on the goal, outside the native environment. Your "goal" is to mimic the native environment, which already assumes the coral is best in the native environment. That's circular, it's only "best" if the goal is "just like the native environment," and that's the thing you haven't argued for, you are assuming it. I gave specific examples to show the fallacy. You didn't address any of them and circled back to health.

Being able to spot gross coral health by eye is a broad observation. Claiming a specific dKH causes better health is a narrow claim. You're using the broad observation to stand in for the narrow claim. One doesn't prove the other. The claim rests in the circular fallacy outlined above.

You made the argument that fast growth makes the skeleton fragile, and fragile means unhealthy. That's your opinion that skeletal strength is a metric that defines health , an assumption, not a given. Your lower dKH argument (slower growth = strong) rests on that assumption, which rests on the two above. It is a circular set of arguments.

Thanks for clarifying. Some things:We know that coral that forces to unnatural grow speed gives fragile sceleton. And thats not a good thing, maybe an assumption, but not a long shot. Also, we know, or at least have theories, that fast growing sceleton also may be an issue as soft tissue formation is not catching up. That we know also from observation with high alk+low nutri. To mimic nature is always a safe way, and I would say that the obligation of evidence is more those who proclaim the unnatural way than those who proclame the natural.
When a coral is stressed of some reason, you will probaly not see it after its too late, like RTN, so if we go back to the theory that supra high alk may be stressfull, that can be obvious when its irrevesible, meaning that a healthy looking coral maybe isnt that tomorow. We also know that there is connection between supra high dKH/Low nutrient and RTN. So I did not turn Randys argument around to not answer the question, but just to say that I rather think it was opposite.
Anyway, there is a risk we loose the main subject here, which still is if a coral can be stressed of not just variation in dKH (that we know) but also by a high baseline value itself. We do not know for sure, so why take the risk and not mimic the nature?

/Jonas

 

[Lasse]

which still is if a coral can be stressed of not just variation in dKH (that we know)

How do we know that?

Sincerely Lasse

 

[Subsea]

I don’t really have an opinion on what is “best”, and I think the answer may depend on your goals.

Randy,
As always, you are so very pragmatic and I thank you for that.

After 55 years, my goal is to keep my reefing addiction simple. To that end, I don’t maintain SPS or LPS so alkalinity management is not a priority. I allow natural buffering to maintain Caribbean lagoons with ornamental seaweeds and diverse filter feeders.

For one reference: http://dx.doi.org/10.1029/2011JC007603
...alkalinity consumption over the reef as well as many other forces are influencing the alk level (and availability) across the reef.

Also, corals probably exert more control over their internal chemistry (and far more easily) than is generally presumed.

I do like "emulate nature" as a general axiom for problem solving in reefing.

Kudoes to emulate nature.

 

[LordClownFish]

My mix reef is exploding at 7.9 with daily doses of TM AFR to keep it at 7.9