herring_fish
Crazy Designer
You can explain anything to sound supposedly true.
I takes it up. You export it. That is a simple as it gets.
I takes it up. You export it. That is a simple as it gets.
Cryptic, Macro, or both?
- Thread starter Lavoisier
- Start date
Squidmotron
New member
Whew
herring_fish
Crazy Designer
I was in a bit of a hurry so I was rather short but if you put Miracle-Gro® in a bucket and add aeration and lighting, it will grow algae. Yes?
If you keep the water but clean out the bucket of it's algae (harvest), and repeat fifty times, you will have a constant phosphate test level from cycle to cycle.
The same would be true of cheato. You would start with a certain amount, add fertilizer, wait and harvest then repeat. Test results would remain constant.
If there are not fish and no corals, then detritus is taken out of the equation (for the most part) but you do have input and exports and a measurable result.
Detritus is a separate argument altogether.
I am not sure but Reefin' Dude was mostly talking about sequestration (goody, I got to work it into a sentence using an obscure definition 9). A lot of that can be taken up in conversations about very very small creatures, water chemistry and sand beds. The decomposition web is not fully understood by anyone yet so there can be lots to talk about and his input is interesting food for thought.
On the other hand, algae does take up nitrates and phosphates along with some other things. That is documented, proven and patented. Stick a fork in it because it's done.
Algae is not the only way to lower nutrient as we all know. Heck, I don't even use cheato. I am an ATS guy but I used to use a skimmer and it worked well for me. I am just commenting on your question.
1] No I haven't. But wish I could one way or the other.
2] I would. http://www.reefcentral.com/forums/showthread.php?t=2267717&highlight=cryptic TMZ does ,plus others im sure. But I lean more that way as opposed to huge skimmer/no substrate/minimal rocks.
But this is more anecdotal rambling so please disregard.
Lavoisier
Premium Member
1] No I haven't. But wish I could one way or the other.
2] I would. http://www.reefcentral.com/forums/showthread.php?t=2267717&highlight=cryptic TMZ does ,plus others im sure. But I lean more that way as opposed to huge skimmer/no substrate/minimal rocks.
But this is more anecdotal rambling so please disregard.
Thanks for the link and the input. The fact is that all we have is anecdotal! I believe I will use the 140g for cryptic and a section in my sump for macro. I have the luxury of adding another macro refugium if I need it.
eyesinthedrk
New member
the other question Lavoisier is what is your reasoning for the things. for example i, like you, want a mandarin. preferably a breeding pair. so my primary reasoning for my fuge is pod production. nutrient export in my case is a secondary benefit.
another fish id love to keep successfully is a morish idol. idols, angles and a few other fish are noted as being sponge eaters in the wild. if/when i add my cryptic zone my primary purpose will be growing sponge to feed the tank. again any water polishing or nutrient reduction will be a secondary benefit for me.
so it all boils down to your reasons for doing them.
another fish id love to keep successfully is a morish idol. idols, angles and a few other fish are noted as being sponge eaters in the wild. if/when i add my cryptic zone my primary purpose will be growing sponge to feed the tank. again any water polishing or nutrient reduction will be a secondary benefit for me.
so it all boils down to your reasons for doing them.
SantaMonica
Well-known member
A finer point about this, is that the shaded part of any macro can die and put nutrients back into the water. So even though you are removing X amount of phosphate via the macro you remove, you might be putting XX amount back into the water because that portion of macro could not be harvested.
So the goal for maximum filtering is to illuminate any and all parts of the macro with full illumination, and to avoid any reduced illumination.
SantaMonica
Well-known member
Well actually, any part of the macro deeper than about 20 mm behind other macro, is pretty much classified as "shaded".
accordsirh22
New member
just to add, from a simple biology standpoint, the more diverse a system is, generally the more stable it is
Reefin' Dude
New member
yes, but it is not very efficient at it. all organisms produce waste. only some of the nitrates and phosphates taken up by algae is actually bound long term by the algae the rest is released. up to 40% of the phosphates taken in by algae is released back into the water column as organic phosphates. not inorganic anymore, but still phosphates none the less.
well, no. how can this be? Chaeto makes more food for more Chaeto? have you found an organism that is more than 100% efficient?
this is where you got it figured out, then you got lost again.
please read up about ATP and ADP to learn about how phosphates are used for energy production without the mass of phosphates being destroyed. organism populations are determined by available food, correct. if there is an ever increasing mass of algae, then there must be an ever increasing mass of food for the organisms, if not than the organisms growth would remain constant or die back if the amount of food goes down. where is the inorganic phosphates coming from to feed the Chaeto? why not just remove the source? Got it.
as long as you do not keep adding more Miracle-Gro. in other words do not feed the tank. this only works until a resource becomes limiting. this could be phosphates, nitrates, CO2, light, or another resource. at any event you will never get to a true 0. you may get to 0.009ppm, but you will not get below that using algae. that is the limit for an oligotrophic system.
you would need to keep adding fertilizer to the tank. do we really want to be adding fertilizer to a tank? fertilizer is readily available nitrates and phosphates. this is absolutely the worst thing we want to be putting into our systems if we are trying to keep our systems even remotely nutrient limited. what we want to add is organically bound phosphates to the system. feed the organisms we bought, then remove their waste products before they have a chance to be broken down by bacteria into inorganic phosphates and nitrates to feed the algae.
until the algae dies, because its source of food is gone, then the algae dies. why is this not going on in our systems?
no need to understand it completely. all organisms bind nutrients. if the more organisms in the system, the more nutrients bound in the system. if those organisms were not there in the first place, than the total mass of the system has increased. the system is becoming more eutrophic. the question is how much decomposition do we actually need in our systems. why not just remove the poo before it decomposes? i say take out the trash instead of waiting to export cockroaches.
yes, an organism binds nutrients, but those nutrients are always in a state of flux. no cel lives forever and when it dies it is expelled. those bound nutrients are now free. only an increasing mass of an organism is taking up more nutrients. if the organism is not increasing in mass, than it is expelling as much mass as it is taking in. how much food do you take in a day? are you constantly gaining mass? why not? if you are, when do you decide to go on a diet? why would we want to go on diets if we are always meant to gain mass until we die?
only when an organisms is growing does it not expel as much mass as it takes in. an increasing total population of an organism will also slowly temporarily increase its bound nutrients. which then brings us to the point of where are all of the nutrients necessary to support the growing population?
i am one that believes the more bio-diversity in a system the less stability. the more populations needing balanced nutrient imports the greater the chance of one of those populations crashing and causing a sudden influx of their bound nutrients to the system. i would much rather just keep the organisms i want and maintain their food and waste imports and exports to maintain their health. just remove their wastes before it has a chance to feed more organisms. what benefit do these other organisms have to the critters i want if i am providing food and remove their wastes?
G~
Nano sapiens
New member
Due to the vast number of different organisms in a natural system (tropical rainforest, coral reef, etc) his whole idea of 'more organisms promotes stabilty' came about. In nature there is a huge 'dilution of pollution' arena known as the earth's biosphere that allows for such fantastic diversity and complex cycling of nutrients performed by these multitudes. In our case, we are concerned with the coral reef environment which is part of an immensely huge sea or ocean. Any waste products that are not used locally are simply diluted and carried away by the constant influx and outflow of oceanic water.
A reef aquarium, obviously, can't operate in the same way. The best we can do is provide substitutes for the processes on a reef and often we have to step in ourselves and perform certain tasks to prevent a system from becoming increasingly eutrophic. Trying to maintain a huge biodiversity as seen on a natural reef is what we would all like, but the reality is that doing so has the potential to destabilize an aquarium system for the reasons 'Reefin' Dude' mentioned.
A reef aquarium, obviously, can't operate in the same way. The best we can do is provide substitutes for the processes on a reef and often we have to step in ourselves and perform certain tasks to prevent a system from becoming increasingly eutrophic. Trying to maintain a huge biodiversity as seen on a natural reef is what we would all like, but the reality is that doing so has the potential to destabilize an aquarium system for the reasons 'Reefin' Dude' mentioned.
herring_fish
Crazy Designer
I guess that where an aquarium is concerned, we just have a different paradigm that we work from. Both of our ways of looking at the life cycles in a tank are quite valid. A more eutrophic system can be good or bad, depending on how you look at it. This is a very old discussion that we would not be able to finish in several books of writing and this is not something that I want to argue here.
The Berlin System is probably not your guiding light but many of its principles are consistent with what you are saying and there are a ton of books written that you could use to back you up.
In the early 90's, I was getting into filter feeders and greatly increased feeding. I was pouring food in and skimming it right back out again and it was working quite well. Then I read Dr. Adey's Dynamic Aquaria and it changed the way that I looked at my little ecosystem. He described several ecosystem around the world, many of which, he and his followers attempted to model. Some of these systems were different parts of the same reefs. He tried to show, through hundreds of studies that he and many others had preformed, that in the wild these systems were incredibly complicated and diverse.
He tried to show that these systems were very robust and more resilient because of their biodiversity. He noted that there were populations of animals, bugs and other organisms that expand and contract to adapt to whatever is in the water column at the time. Many of these organisms act as built in redundancies so crashes are less likely. He described and demonstrated that more nutrients are bound in, what he might call a healthy system's water column than previously believed. He described and modeled lean fore reefs and rich lagoons. He also linked them together. That is where we got the refugium. He modeled cryptic zones as well. He also described how many of these redundancies can be modeled into a smaller closed systems and explored some of their limitations and strengths. It is amazing how many of these organisms come into a tank as hitchhikers and can be promoted with the right modeling.
Yes a lean system works great and so does a rich one. It is just what you are going for. I found that feeding a lot of food and waiting for it to rot and then getting rid of the byproducts left me with corals that were just as healthy as in my previously leaner system.
Algae may be inefficient but it works. I can keep adding food and the leftovers can become fertilizer. You would use the work eutrophic and so does Dr. Adey. He might also call it robust. Yes there are more nutrients bound up in the food chain but as long as there is sufficient export, the system stays healthy and rich in diverse foods for coral and other organisms alike.
The algae takes nutrients up and it grows and I harvest it. It's pretty simple but if you don't like that idea, I can certainly see why. All that I know is that the science is valid and it works for me. It's not the only way to go but it is one way among many that works. Many people use skimmers instead of, or in combination with algae and still strive to have a rich system. Other use algae but want to have a lean system. Go figure.
There are lots of ways to go. That is what makes reefing fun. Yes?
The Berlin System is probably not your guiding light but many of its principles are consistent with what you are saying and there are a ton of books written that you could use to back you up.
In the early 90's, I was getting into filter feeders and greatly increased feeding. I was pouring food in and skimming it right back out again and it was working quite well. Then I read Dr. Adey's Dynamic Aquaria and it changed the way that I looked at my little ecosystem. He described several ecosystem around the world, many of which, he and his followers attempted to model. Some of these systems were different parts of the same reefs. He tried to show, through hundreds of studies that he and many others had preformed, that in the wild these systems were incredibly complicated and diverse.
He tried to show that these systems were very robust and more resilient because of their biodiversity. He noted that there were populations of animals, bugs and other organisms that expand and contract to adapt to whatever is in the water column at the time. Many of these organisms act as built in redundancies so crashes are less likely. He described and demonstrated that more nutrients are bound in, what he might call a healthy system's water column than previously believed. He described and modeled lean fore reefs and rich lagoons. He also linked them together. That is where we got the refugium. He modeled cryptic zones as well. He also described how many of these redundancies can be modeled into a smaller closed systems and explored some of their limitations and strengths. It is amazing how many of these organisms come into a tank as hitchhikers and can be promoted with the right modeling.
Yes a lean system works great and so does a rich one. It is just what you are going for. I found that feeding a lot of food and waiting for it to rot and then getting rid of the byproducts left me with corals that were just as healthy as in my previously leaner system.
Algae may be inefficient but it works. I can keep adding food and the leftovers can become fertilizer. You would use the work eutrophic and so does Dr. Adey. He might also call it robust. Yes there are more nutrients bound up in the food chain but as long as there is sufficient export, the system stays healthy and rich in diverse foods for coral and other organisms alike.
The algae takes nutrients up and it grows and I harvest it. It's pretty simple but if you don't like that idea, I can certainly see why. All that I know is that the science is valid and it works for me. It's not the only way to go but it is one way among many that works. Many people use skimmers instead of, or in combination with algae and still strive to have a rich system. Other use algae but want to have a lean system. Go figure.
There are lots of ways to go. That is what makes reefing fun. Yes?
Nano sapiens
New member
I have read a great many of the books, articles and papers put forth by people like Dr. Shimek, Dr. Adley, Julien Spring, Charles Delbeek, Eric Borneman, John Tullock and many more. I have been enriched by what they have to say, even if I don't always agree with some of their methodologies.
My 'reefkeeping' experience goes back to the very early 80's where I built a system from a magazine description of how some Germans in Berlin were having some success in keeping corals. I used a 12g tank as the DT and a second tank 10g raised above the other as a sump, an empty canister filter to move water up to the sump, siphons to bring it back down to the DT, got my hands on a 'state-of-the-art' Sanders protein skimmer and used lava rock/sand in trays to produce a 'wet/dry' filtration system. LR came in 'wet' air-freighted from the Caribbean, so was full of organisms such as gorgeous live sponges and such (nearly all of which perished, unfortunately). I had very little idea about nutrient enrichment so occasional water changes were the norm, the substrate was ignored and less than optimal GAC was changed out occasionally. This setup grew Zoanthids like nothing I've ever seen since, but would have likely collapsed if I had run it longer than the two years it was up-and-running.
It is apparent that different nutrient levels should be maintained for different types of systems. A nutrient rich system should allow for increased bio-diversity, and as you stated, much will come in on live rock and multiply if conditions are conducive to survival. But, the bio-diversity will always be a far cry from what one finds in nature and I don't think this is a bad thing at all.
In running a small Nano tank for five years, in contrast to my much larger previous systems, it became very apparent that a reduced bio-diversity was not at all detrimental to the system as I had always read from many of the 'experts'. On the contrary, in a small system where every death has a lot more influence on the system's health, a reduced sub-set of creatures has proven to be very stable and resilient.
I'm not an 'oligotrohic' purist by any means and I believe in maintaining an environment that suits the organisms being kept. Some organisms flourish in more eutrophic systems and keeping such a system for them is logical and certainly justified...and others flourish in an oligotrophic environment.
What I see as the biggest problem, especially for new reefers, is developing an understanding that a system that continuously increases in eutrophication will at some point collapse. This is where the term 'eutrophic' gets its unjustified bad rap IMO.
My 'reefkeeping' experience goes back to the very early 80's where I built a system from a magazine description of how some Germans in Berlin were having some success in keeping corals. I used a 12g tank as the DT and a second tank 10g raised above the other as a sump, an empty canister filter to move water up to the sump, siphons to bring it back down to the DT, got my hands on a 'state-of-the-art' Sanders protein skimmer and used lava rock/sand in trays to produce a 'wet/dry' filtration system. LR came in 'wet' air-freighted from the Caribbean, so was full of organisms such as gorgeous live sponges and such (nearly all of which perished, unfortunately). I had very little idea about nutrient enrichment so occasional water changes were the norm, the substrate was ignored and less than optimal GAC was changed out occasionally. This setup grew Zoanthids like nothing I've ever seen since, but would have likely collapsed if I had run it longer than the two years it was up-and-running.
It is apparent that different nutrient levels should be maintained for different types of systems. A nutrient rich system should allow for increased bio-diversity, and as you stated, much will come in on live rock and multiply if conditions are conducive to survival. But, the bio-diversity will always be a far cry from what one finds in nature and I don't think this is a bad thing at all.
In running a small Nano tank for five years, in contrast to my much larger previous systems, it became very apparent that a reduced bio-diversity was not at all detrimental to the system as I had always read from many of the 'experts'. On the contrary, in a small system where every death has a lot more influence on the system's health, a reduced sub-set of creatures has proven to be very stable and resilient.
I'm not an 'oligotrohic' purist by any means and I believe in maintaining an environment that suits the organisms being kept. Some organisms flourish in more eutrophic systems and keeping such a system for them is logical and certainly justified...and others flourish in an oligotrophic environment.
What I see as the biggest problem, especially for new reefers, is developing an understanding that a system that continuously increases in eutrophication will at some point collapse. This is where the term 'eutrophic' gets its unjustified bad rap IMO.
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herring_fish
Crazy Designer
Why would a rich system eventually collapse?
I understand that if a beginner throws a lot of stuff in a system without understanding it, this could be a recipe for disaster but I would think that a well design system can be very rich and never collapse. Systems collapsed a lot more in the old days than they do now. Are you saying that the problem is that new comers just don't understand the subtleties of a well designed rich system? If so, I agree.
Julien Sprung and others were not initially big fans of richer systems but have come around right?
By the way, one of the things that happens in a diverse system is that some of the nutrients are bound by ever more organisms but these organisms burn calories just by existing. More organisms mean more variety of food particle sizes and forms so there are more opportunities for more diversity of corals that can eat them. I would expect that if a coral dies of old age or any other reason, that you would remove it from the tank, there by exporting nutrients.
I too have put things in the tank that it was not rich enough to successfully feed. I got some large sponges that grew well at first but when they ran out of what they needed in my tank they started to brown and I had to remove them. Instead, I have started slowly, adding more and more food as the tank can handle it. I use test kits to tell me how fast to go.
As my tank becomes more mature and more diverse, most of the people that you listed would say that it is becoming more stable not less. I have more sponges and a myriad of other things that live on excess food but I do have to have something that exports what is not consumed. You do need to have significant export in most any system. That is a given.
I am not, for a second, trying to suggest that eutrophication or richness is a substitute for export but I would have to go with those experts that you mentioned. It is consistent with my experience.
When the question is asked, do you want to have a macro or a cryptic zone or both, I guess I would not vote for neither but we can just disagree. I just don't think that hardly any evidence points toward an eventual collapse because it is diverse.
Nano sapiens
New member
I mentioned an increasingly eutrophic situation, so basically one where the tank get richer and richer with nutrients. There comes a point where the nutrients are just too high and the system 'crashes' as the organisms within die in a chain reaction effect. Tanks still crash a lot, especially Nano tanks, where bad things happen very quickly.
True, but what I believe Julien and Delbeek were realizing after their 1st volume of 'The Reef Aquarium' is that aquarists were starving their fish and corals due to a fear of feeding the tank due to increasing PO4 and NO3. Improved export methods and products have enabled aquarists to feed more without polluting the system.
A large and diverse bio-load is very nice for the aquarist, but also a double-edged sword. If something unforetold should happen (extended power outage and resultant rapid oxygen depletion, death of a large organism/group of organisms, etc.) there is less margin of error. A large dying organism can very quickly destabilize a system and start a cascade effect if it is not immediately removed from the system. Removing it would remove some of the tank's biomass, of course. As far as more food of different sizes being available for the corals, I can see where different types and sizes of larvae would be of benefit. In lieu of these it is up to the aquarist to provide proper food types and sizes. As in most things in life, there are +s and -s.
That is the best approach IMO. I started my tank with small frags and let them grow in to the environment, instead of placing large specimens into the tank and hoping for the best. But I also understand those that want a 'filled in' look right away.
It has long been known that a 'mature' system is best for sensitive species. 'Stability' in this sense is largely due to robust and stable bacterial populations that develop with time that can efficiently process nitrogenous 'waste', thus avoiding spikes in the nitrogen cycle. I believe it has less to do with having more or less species in the tank, but I do believe that a healthy system should have at least those species present that can perform beneficial functions (herbivores and detritivores). The rest are what we ultimately like to keep, be it corals, anemones or something else, but these may or may not perform a beneficial function in the system besides being pleasant to look at.
I look at it this way. The 'richness' of a system should reflect the main attraction organisms in the tank, usually corals, anemones, etc. Once the correct level of nutrients is reached, then it is the aquarist's job to maintain equilibrium through balanced input vs. export. We get into trouble when the system becomes unbalanced, either one way or the other.
No one is saying that a diverse system will definitely collapse and no one is saying a not-very-diverse system is immune to collapse. As an extreme example, in our small captive systems (they are all small when compared to a natural reef system) if one were to try and cram every species of organism in there just to have 'diversity and stability', you'll end up with a very real potential for disaster. At the other extreme you could have a system so sparce in organisms that it wouldn't be a real system at all. Like everything, it's a matter of balance and how one quantifies their concepts.
Here's what I mean. I have a 12g tank that contains about (25) Ricoridas, (2) Discsoma species, (9) species of SPS, (4) species of LPS, (5) types of Palys and Zoas, (1) small bi-valve, Hermit Crabs, Collonista Snails, Bristleworms, small sponges and a few limpets. For some, this is a 'diverse' system (my guess is that 'Reefin' Dude' would think so), but for others the system would still need Macro Algae, larger snails, perhaps a cleaner shrimp, a Pom-Pom crab, maybe a small clam or two and throw in an anemone to round things out. Based on what others have in their mature tanks, I consider my system as less diverse than the norm.
Would the system tend to be more 'stable' with all those additional creatures than it is today, even if the bio-mass were the same in relation to both scenerios? I would say 'no', it would not be. However, the system could still potentially work just fine, assuming that the creatures added are compatible.
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herring_fish
Crazy Designer
Cool
Reefin' Dude
New member
i am also one that believes we need to stop suggesting a single type setup for all biotopes, and for all coming to the hobby. the organisms we keep can all come from very specific environments, and to think that we can put them all into the same glass box setup the same is a bit crazy.
i think we as aquarist put to much emphasis on the nitrogen cycle and not enough emphasis on understanding how phosphates and the nitrogen bacteria interact. it is not the nitrogenous compounds that cause people to leave the hobby, it is the phosphates. yet, all we are told is to keep feeding down, without actually going into how phosphates are needed for all living organisms including the bacteria that are converting nitrogenous wastes. they all work hand in hand.
no population can grow indefinitely in a limited space. at some point if the food keeps increasing the population is going to crash. if the population is increasing, than therefore the food is increasing. there is going to be a level where temporarily "binding" of nutrients is going to plateau before it crashes. when i say crash i mean a change from nutrients temporarily bound in the organisms we want and then becoming bound in organisms we do not want. the nutrients are not going anywhere, they are just being temporarily bound in other organisms. because calcium carbonate is such a fantastic phosphate binder it can take years before a system will reach this tipping point. it is because of this, that aquarists were led to believe that nutrients are actually being process indefinitely instead of just slowly increasing over time. aquarist would give credit to the multicellular organisms instead of the calcium carbonate and the bacteria. you can fit a lot of bacteria in between the grains of a fine substrate. which is not a bad thing, but just like litter box at some point someone needs to empty it.
G~
i think we as aquarist put to much emphasis on the nitrogen cycle and not enough emphasis on understanding how phosphates and the nitrogen bacteria interact. it is not the nitrogenous compounds that cause people to leave the hobby, it is the phosphates. yet, all we are told is to keep feeding down, without actually going into how phosphates are needed for all living organisms including the bacteria that are converting nitrogenous wastes. they all work hand in hand.
no population can grow indefinitely in a limited space. at some point if the food keeps increasing the population is going to crash. if the population is increasing, than therefore the food is increasing. there is going to be a level where temporarily "binding" of nutrients is going to plateau before it crashes. when i say crash i mean a change from nutrients temporarily bound in the organisms we want and then becoming bound in organisms we do not want. the nutrients are not going anywhere, they are just being temporarily bound in other organisms. because calcium carbonate is such a fantastic phosphate binder it can take years before a system will reach this tipping point. it is because of this, that aquarists were led to believe that nutrients are actually being process indefinitely instead of just slowly increasing over time. aquarist would give credit to the multicellular organisms instead of the calcium carbonate and the bacteria. you can fit a lot of bacteria in between the grains of a fine substrate.
which is not a bad thing, but just like litter box at some point someone needs to empty it. G~
Nano sapiens
New member
I went back and looked at the OP's original post and we are off a bit on a tangent, but hopefully still of use to the OP.
I personally enjoy a 'mixed reef' tank and I am fully aware of the challenges. When setting up this type of system I believe that the aquarist should take into account the needs of all the animals, but design the system for the most sensitive species. For example, if Acropora are kept the system should be low nutrient which means that other tank species with higher nutrient requirements must somehow also meet their energy demands. For many of these organisms, this can be accomplished with sufficient target feedings, as opposed to broadcast feedings, so as to maintain good water quality. Luckily, most corals derive nutrition through multiple pathways and will exploit whichever one(s) provide the nutrition that they require. I have had success with this strategy keeping many different organisms together, but it requires a bit more dedication and observation to ensure all are doing equally well.
One other challenge is that aquarists may not know the optimal requirements or tolerances of a species. For example, with Acropora we are generally safe taking the approach that 'low nutrient' water is optimal. But in nature, one can find Acros in extremes from very low nutrient oceanic fore-reef locations, to low or moderate nutrient inshore reefs, to relatively high nutrient lagoon environments. Sometimes the same species can be found doing well in all three locations! This to me shows that corals can be remarkably adaptable, but there are limits.
I personally enjoy a 'mixed reef' tank and I am fully aware of the challenges. When setting up this type of system I believe that the aquarist should take into account the needs of all the animals, but design the system for the most sensitive species. For example, if Acropora are kept the system should be low nutrient which means that other tank species with higher nutrient requirements must somehow also meet their energy demands. For many of these organisms, this can be accomplished with sufficient target feedings, as opposed to broadcast feedings, so as to maintain good water quality. Luckily, most corals derive nutrition through multiple pathways and will exploit whichever one(s) provide the nutrition that they require. I have had success with this strategy keeping many different organisms together, but it requires a bit more dedication and observation to ensure all are doing equally well.
One other challenge is that aquarists may not know the optimal requirements or tolerances of a species. For example, with Acropora we are generally safe taking the approach that 'low nutrient' water is optimal. But in nature, one can find Acros in extremes from very low nutrient oceanic fore-reef locations, to low or moderate nutrient inshore reefs, to relatively high nutrient lagoon environments. Sometimes the same species can be found doing well in all three locations! This to me shows that corals can be remarkably adaptable, but there are limits.
