why is it so hard to keep nutrients these days

[Nano sapiens]

23 minutes ago, jservedio said:

Honestly, I don't really know where the cutoff would be or where it becomes noticeable, I just know that multi-year growth with  >=0.1ppm PO4 makes acros and montis in particular incredibly brittle. I'll try and pay more attention now that I'm bringing my phosphates down quite a bit in the 50g to see if it persists or if it was the phosphate that was solely responsible for the issue, but I'm not sure what else would lead to skeletal problems like that since my other parameters are within the typical ranges (albeit alk on the lower end). I will say that my growth speed for SPS is definitely below average because I keep my lighting comparatively very low to other SPS dominant tanks because I push for really good LPS coloration, but I don't think that would lead to brittleness issues since I never had brittleness until I brought my nutrients way up.

 

https://www.sciencedirect.com/science/article/abs/pii/S0022098111004588

 

"It is suggested that the phosphate enhanced growth was due to increased zooxanthellar populations and photosynthetic production within the coral. Skeletal density reduction may be due to phosphate binding at the calcifying surface and the creation of a porous and structurally weaker calcium carbonate/calcium phosphate skeleton. Increased phosphate concentrations, often characteristic of eutrophic conditions, caused increased coral growth but also a more brittle skeleton. The latter is likely more susceptible to breakage and damage from other destructive forces (e.g., bioerosion) and makes increased coral growth a poor indicator of reef health."

 

 

https://reefs.com/magazine/coral-growth/

 

"However, the price for coral growth in higher nutrient water is that the skeleton produced is less dense and hence more brittle, which has been observed in both corals and giant clams that were grown under higher levels of ammonia and nitrate (Fitt et al., 1993; Carlson, 1999; Marubini and Flake, 1999)"

 

Interesting that substantial increases in ammonia, nitrate and phosphate, too, can cause skeletal brittleness.

[seabass]

1 hour ago, jservedio said:

I'm not sure what else would lead to skeletal problems like that

I'm not sure either.  Low pH might potentially contribute.  I feel that I've read climate change articles which state that low pH due to high CO2 levels might do something like this.  With stony corals, it's always hard to rule out alkalinity (or calcium, magnesium, or even certain trace elements like strontium).  Then there are reactions that might not be quite as obvious (similar to how ultra low nutrient systems, with intense lighting, tend to burn corals in high alkalinity saltwater).  But I agree, there seems to be a direct correlation between high phosphate and skeletal density which isn't easily dismissed.

[jservedio]

1 hour ago, Nano sapiens said:

Interesting that substantial increases in ammonia, nitrate and phosphate, too, can cause skeletal brittleness.

Thanks! I hadn't read these particular studies until now, but have read others about incorporation of phosphate into skeletal structure causes less density and more brittleness. Interesting that nitrates and ammonia do the same. My nitrates were comparatively less high, normally between 10-25ppm (though, I tested far, far less frequently and was using an expired kit for a lot of it, so just estimates), so I'd tend to point the finger squarely at phosphates.

 

28 minutes ago, seabass said:

I'm not sure either.  Low pH might potentially contribute.  I feel that I've read climate change articles which state that low pH due to high CO2 levels might do something like this.  With stony corals, it's always hard to rule out alkalinity (or calcium, magnesium, or even certain trace elements like strontium).  Then there are reactions that might not be quite as obvious (similar to how ultra low nutrient systems, with intense lighting, tend to burn corals in high alkalinity saltwater).  But I agree, there seems to be a direct correlation between high phosphate and skeletal density which isn't easily dismissed.

Low pH definitely makes calcification more difficult, but I don't know if that would alter the physical skeletal structure like incorporating more phosphate or apparently even nitrate and/or ammonia would. In any case, I can rule low pH out as I had pretty high pH by way of dosing ~1.5 dkh/day entirely through kalk - always over 8.2 on the American Pinpoint Probe when I tested. In fact, if I hadn't maintained a fairly low alkalinity of 7 dkh, my pH probably would have been well into unacceptable levels. Strontium and Iodine were both right within standard range, at least according to hobby grade kits and I only tested a handful of times since it was always fine.

 

Magnesium fluctuated a bit from my normal ~1250ppm to about 2,000ppm for a couple months 4 or 5 years ago when I added more dry rock to try and help with the GHA on the new rocks, but that was before I added any of my acros. CA an Alk were stable for many years without any major spikes, so I don't think it was that.

 

Pretty much the only thing out of the ordinary about my tank was the high inorganic phosphate levels (and I'd imagine massive levels of organics due to the detritus in the sump), so I think it's the most reasonable explanation, but definitely would love to find other possible causes to rule out!

 

BTW, thanks for all of the replies as well. Every time I discuss stuff with you and/or nano_sapiens, I always end up learning something new or getting something new out of studies I'd previously read.

[seabass]

7 minutes ago, jservedio said:

would love to find other possible causes to rule out!

[Nano sapiens]

24 minutes ago, jservedio said:

BTW, thanks for all of the replies as well. Every time I discuss stuff with you and/or nano_sapiens, I always end up learning something new or getting something new out of studies I'd previously read.

 

YW. 

 

I might have a tid-bit or two to throw out there once in a while, but maybe not so much fun at parties?

 

"Did you hear the one about..."

 

"No, but did you know that ammonia is less metabolically expensive for corals to use than nitrate?"

 

...dead silence in the room 

 

 

[mcarroll]

On 4/16/2021 at 11:31 AM, seabass said:

I don't actually know anybody who is maintaining their tank's phosphate levels at 0.50 parts per million (or about 5 times higher than what's typically considered "high", or around 10 times higher than the upper end of what's frequently recommended).

🙋‍♂️

 

My system has been pegging the Salifert PO4 test (and NO3 test) for the last year or so....by now, that's most of the time this tank (an upgrade) has been running.

 

On 4/16/2021 at 11:31 AM, seabass said:

Care to comment on this topic?

The bogeyman of high phosphates is one of the worst in terms of coral care.

 

For reference, I've saved several of the relevant articles that I've bumped into on this topic over the years on my blog (reefsuccess.com) and you can find them in the Coral or Nutrients sections.

 

Here's the short list:

"Tissue and skeletal changes in the scleractinian coral Stylophora pistillata Esper 1797 under phosphate enrichment"

"Control of phosphate uptake by zooxanthellae and host cells in the scleractinian coral Stylophora pistillata"

"High phosphate uptake requirements of the scleractinian coral Stylophora pistillata"

"Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean"

 

As far as I'm concerned from what I have read so far there is no downside to stony corals of living with "high" phosphate levels, per se.  

 

None. 

 

The "light skeletons" from growing in PO4-enriched water that is documented in the literature are merely a change in growth form.  Calling that change "bad" or "unhealthy" is a judgement applied by the workers doing the research which was not implied by the research itself.  There was nothing in the reasearch that indicated the corals were stressed or unhealthy in any way – the skeletons were just lighter.

 

In my estimation, having a lighter skeleton isn't a detriment if vegetative reproduction (ie fragging) is one of the gene-spreading tools in your bag.

 

High PO4 = light skeleton

light skeleton = higher rate of fragging

more fragging = more instances of that coral

more instances of that coral = successful life strategy

 

I think back in the day folks paid less attention to nutrients AND had less tools available to manipulate nutrient levels, and that meant a few different things....almost all of them good.

 

Today we have some more awareness, and lots of people dosing their tanks with nutrients....which should be a good thing.  

 

But we also have more problem tanks these days because of these tools...increasing popularity of tools like carbon dosing and GFO have REALLY increased the rate of problems.  (Adding dead rock into the mix later on did not help anyone.)

 

Unfortunately, awareness isn't very comprehensive AND it does not come with wisdom:  lots of newbs today still fire up a tank and immediately load it down with excessive amounts of mechanical, biological and chemical filtration of all types.....then blame the protein skimmer (or lights, or salt) for their problems.  😬

 

I wish I knew how to prevent all that.  But the established pattern seem to be that folks rarely seem to read up first or show up asking questions first before starting a tank....seems most common to see someone start a tank "offline" and then show up with problems...and (maybe) then read up.   That makes for a tough start and a not-very-satifying tank experience.

 

P.S.  Growing faster, as corals do under "high" PO4 levels, does come with a relative cost that may be of interest: Fast Growth May Impair Regeneration Capacity in the Branching Coral Acropora muricata.

 

I hope this is of interest to some folks – pls drop a comment on any of those articles if you like them!

[natalia_la_loca]

If people had more convos like this one at parties, I’d go to more parties 🍻

[Reefkid88]

I'm actually having the same issue at the moment. I cannot keep ant phosphates or nitrates in my tank. Both have been at 0ppm for 7 months. My PH has always been on the lower end too,like 7.2-7.6. 

 

 I run the smallest amount of carbon,my tank only gets 1 water change a month,when I am gone at work,I have my wife feed heavy with Seachem Fuel and BRS copepods and rotifers. When I get home I do a ¾-1g WC and replace carbon. 

 

 I am assuming this is why my zoa's have grown so slow and don't look 110% like they should. They took off the first couple of weeks then BOOM stopped spreading. I think majority of the reason my Acan's still grow is because they get fed so much lol. 

 

 I have always kept about 5ppm of nitrates and just enough phosphates to get colors on my color chart regardless if the test kit is Red Sea,Salifert or API. I have NEVER had a problem KEEPING nitrates in a tank until this one. But thankfully being away a month at a time,no big changes are able to be made to correct them. In fact,I basically gave up lol and that is probably why my coral and tank still probably look as good as possible with having such low nutrients. 

 

 The only critters I have in the tank is a single hermit and a Pincushion Urchin. I have thought about buying a bottle of ESV Nitrates to periodically dose to see if that helps things. 

[jservedio]

5 hours ago, mcarroll said:

As far as I'm concerned from what I have read so far there is no downside to stony corals of living with "high" phosphate levels, per se.  

 

None. 

 

The "light skeletons" from growing in PO4-enriched water that is documented in the literature are merely a change in growth form.  Calling that change "bad" or "unhealthy" is a judgement applied by the workers doing the research which was not implied by the research itself.  There was nothing in the reasearch that indicated the corals were stressed or unhealthy in any way – the skeletons were just lighter.

I would very much agree that it isn't unhealthy or bad for your corals to grow in a high phosphate environment and I obviously had a high phosphate tank for years and years, but you are very much downplaying issues reefers will have when it comes to branching SPS with brittle skeletons. Even at just 0.15ppm, the change in density is enough where branches will just start to break under their own weight as they grow. While this may not be hurting the SPS colony itself, it is a huge downside for the owner of the tank and is something that's pretty much permanent.

 

The super brittle skeleton also doesn't break as cleanly as a more dense skeleton -  instead of a clean cross-branch break, it tends to break at odd angles and shatter leaving incredibly jagged wounds. It looks like the difference between a tree branch being ripped off vs. being cut cleanly with a saw. This makes the other problem you pointed out far more apparent:

5 hours ago, mcarroll said:

P.S.  Growing faster, as corals do under "high" PO4 levels, does come with a relative cost that may be of interest: Fast Growth May Impair Regeneration Capacity in the Branching Coral Acropora muricata.

And it's not just the speed at which corals regenerate, but the structure of the repair as well. Instead of a new axial corallite growing from the break and starting up a new branch from where the old one broke, you get weird, confused structures like this that take forever to completely repair. This A. Austera is ~180 days on from a jagged break where a branch fell off under it's own weight while the rest of the colony has put on probably 6-8" of new branch growth in the same time:

 

 

If you don't keep branching SPS, you will never have to worry about any of these problems, but if you are planning on an SPS dominant tank, this is a very big issue.

[Koleswrath]

@jservedio, @Nano sapiens, @seabass Thank you! This thread and it's links really helped clarify some important questions I've had regarding why my P04 is being consumed so fast in my tank and has made me consider other important factors in my reef keeping methods. It's not your typical humdrum "keep your P04 at 0.03-0.1" conversation. Especially appreciated is the consideration of the point of view of the aquarist and not just the strict biology. Feel free to take up the discussion where it was left off. You guys were riffing pretty good. And if not, maybe some new folks will read this now that it's bumped and learn something new.

 

[mcarroll]

On 4/19/2021 at 9:46 AM, Reefkid88 said:

feed heavy with Seachem Fuel and BRS copepods and rotifers.

Fuel might be helping to suppress nutrient levels.  It's likely "fueling" bacteria growth more than anything else.

 

1 hour ago, Koleswrath said:

It's not your typical humdrum "keep your P04 at 0.03-0.1" conversation.

LOL.   😉   

 

The numbers might be "hum drum" if you are unfamiliar with their origins.  (They are just numbers, after all)

 

But at least IMO they are some of the most important numbers to come into the hobby.

 

I'm not sure many folks were (or are) aware of the relationship between phosphate and photosynthesis.  The subject of phosphate got WAY more interesting once that connection was made for me.  It's not just an excuse to use GFO!!!  😄 

[TheKleinReef]

On 4/19/2021 at 3:49 AM, mcarroll said:

My system

cool lets see it

 

[mxpro32]

interesting stuff.  I've been struggling with the same thing.  I just got back into the hobby after a 18 year break.  back then everyone was trying to keep phosphate and nitrates low.  my new tanks (one has been set up 3 years, the other is new) can't keep the phosphates or nitrates up.  I have been feeding more to increase nitrates and dosing phosphates.  one of my old tanks grew soft coral and lps with almost no intervention.  I never added anything and rarely did water changes.  my ricordias would constantly reproduce and spit off the rock.  my frogspawns grew and split like crazy.  now my corals look mad if I don't add phosphates.  its weird.  my new tanks use dry live rock though.  I think their might be something to that.  

[seabass]

The history of nutrient level recommendations is kind of interesting.  For a long time, the goal was to keep nutrient levels as low as possible, as there are many natural reefs which contain very low levels.  Also, it was known that it was possible to make phosphate a limiting factor in algae growth.

 

Plus, we try to mimic natural seawater levels for many of our reef tank's water parameters.  Although we have found that certain parameters don't have to match all that closely.  For example, we've discovered that it's possible to maintain a reef tank's alkalinity level anywhere between 7 and 12 dKH.

 

Some other parameters, such as calcium and magnesium can also be maintained in higher than natural seawater levels.  And, to a point, even ammonia can safely exceed natural reef levels.  So it shouldn't surprise us too much when we see that reef keepers are now commonly maintaining higher nutrient levels.

 

The main problem with using nutrient levels as a limiting factor to control algae growth, was that it also became a limiting factor for the symbiotic zooxanthellae within corals.  Yes, stony corals can capture some of their own food, but photosynthetic corals still need light and nutrients to sustain themselves.

 

Then, pests like dinoflagellates have been found to bloom in nutrient poor waters (in water where its competition might be struggling).  We've discovered that maintaining higher nutrient levels can help support a more diverse ecosystem within our tanks, as well as helping to support better coral health.

 

Today, we see more about maintaining minimum nutrient levels than about restricting them.  I think about nutrients in a similar manner as minerals (dosing them when needed).  Sure, over feeding will increase both phosphate and nitrate; however, over feeding can also lead to problems due to excess organics.

[mcarroll]

10 hours ago, seabass said:

The history of nutrient level recommendations is kind of interesting.  For a long time, the goal was to keep nutrient levels as low as possible, as there are many natural reefs which contain very low levels.  Also, it was known that it was possible to make phosphate a limiting factor in algae growth.

 

Plus, we try to mimic natural seawater levels for many of our reef tank's water parameters.  Although we have found that certain parameters don't have to match all that closely.  For example, we've discovered that it's possible to maintain a reef tank's alkalinity level anywhere between 7 and 12 dKH.

 

Some other parameters, such as calcium and magnesium can also be maintained in higher than natural seawater levels.  And, to a point, even ammonia can safely exceed natural reef levels.  So it shouldn't surprise us too much when we see that reef keepers are now commonly maintaining higher nutrient levels.

 

The main problem with using nutrient levels as a limiting factor to control algae growth, was that it also became a limiting factor for the symbiotic zooxanthellae within corals.  Yes, stony corals can capture some of their own food, but photosynthetic corals still need light and nutrients to sustain themselves.

 

Then, pests like dinoflagellates have been found to bloom in nutrient poor waters (in water where its competition might be struggling).  We've discovered that maintaining higher nutrient levels can help support a more diverse ecosystem within our tanks, as well as helping to support better coral health.

 

Today, we see more about maintaining minimum nutrient levels than about restricting them.  I think about nutrients in a similar manner as minerals (dosing them when needed).  Sure, over feeding will increase both phosphate and nitrate; however, over feeding can also lead to problems due to excess organics.

+1

 

In addition to everything already mentioned, it was also less possible to achieve zero-nutrient levels back then.   There was a time before GFO.  There was a time before accurate PO4 test kits.  Etc.