Refugium -- Yay or Nay

[CHSUB]

i have been in this hobby for quite a long time. i have been reading and studying up on the phosphate cycle for almost as long once i learned a little more about what it actually is and how it pertains to our systems. there are a lot of deeeeeep rabbit holes of information that deal with phosphates and how our systems work with and against the supply of phosphates. we need to understand them in order to actually progress in this hobby. i do not have all of the information, but i think i have a good start on it.

reefin dude, i think you should put down your text book and study your tank more. trying to achieve ocean reef water parms in a reef tank is almost impossible and really not necessary! i have seen many outstanding reef tanks with high no3 and po4.

 

[Reefin' Dude]

now i am confused. everyone suggests that we should emulate nature, but if somebody puts some numbers down to what nature actually is, they are told to disregard it? how is this hobby suppose to progress with conflicting information like that? i though the point was to emulate a part of the reef? if the reef water is 0.005ppm phosphate, than we should look at ways to achieve that. these organisms we are trying to keep have evolved to live in these conditions for longer than we have been reefing. wouldn't it make sense to match these levels if we are wanting to keep them as healthy as possible? just because our test kits do not have the resolution now, does not mean we just have to give up. use other means of testing. use algae, use other organisms. the tank tells us where we are trophic wise, we just need to read the signs. every organism has an environmental sweet spot. we just need to read more into these and use these to adjust our levels. what algae lives on the outer reef? does Chaeto, no, why? if it doesn't, then why do we have it in our systems if we are wanting to keep outer reef corals?

G~

 

[GroktheCube]

eutrophication is just the build up of nutrients, mainly phosphates and nitrates. they can be in both organic and inorganic forms. we are just able to test for inorganic phosphates. all living organisms contain phosphates. if there is total increase in the total biomass of the system, then the system as a whole is becoming more eutrophic. as long as the biomass that is increasing is what we want (say corals and the fish growing), then we can control the total amount of eutrophication in the system. when the biomass is increasing because of "biodiversity", then there is a definite increase in total nutrients in the system. all organisms produce waste. waste contains nitrates and phosphates. unless this waste is removed it just adds to the total mass of nutrients in the system. if we are always adding food, then the exports must equal the exports in order to maintain the trophic level of the system, minus the amount of nutrients needed for growth i the biomass of the organisms we are wanting to keep.

I've always understood eutrophication to specifically refer to an increase in dissolved nutrients, usually inorganic N+P, and usually in a body of freshwater. In FW lakes, biomass often plays into the measurement of trophic state index (which is usually a measure of chlorophyll [algae], P, and turbidity), but I don't think that can be directly applied to SW systems or tanks. Coral reefs are able to support levels of biomass (and planktonic life) that far exceeds a eutrophic FW lake without any negative effects on biodiversity or dissolved oxygen. I'd argue that the same is true for our tanks. More life != eutrophication if a tank is well managed.

An increase in biomass does not necessarily come along with an increase in dissolved nutrients.

If nutrients are stored, bound, or utilized (as they are on a coral reef), then the degree to which nutrients must be exported relative to imports decreases proportionally. In other words, if imports </= exports + growth + sequestration, no eutrophication occurs. However, if imports > exports + growth + sequestration, levels of dissolved nutrients increase, resulting in a process akin to eutrophication. An increase in biomass is not deleterious to a system (and an increase in biodiversity is quite beneficial), provided that increase does not exceed the carrying capacity of the system in one way or another.

 

[CHSUB]

now i am confused. everyone suggests that we should emulate nature, but if somebody puts some numbers down to what nature actually is, they are told to disregard it? how is this hobby suppose to progress with conflicting information like that? i though the point was to emulate a part of the reef? if the reef water is 0.005ppm phosphate, than we should look at ways to achieve that. these organisms we are trying to keep have evolved to live in these conditions for longer than we have been reefing. wouldn't it make sense to match these levels if we are wanting to keep them as healthy as possible? just because our test kits do not have the resolution now, does not mean we just have to give up. use other means of testing. use algae, use other organisms. the tank tells us where we are trophic wise, we just need to read the signs. every organism has an environmental sweet spot. we just need to read more what algae lives on into these and use these to adjust our levels. the outer reef? does Chaeto, no, why? if it doesn't, then why do we have it in our systems if we are wanting to keep outer reef corals?

G~

i enjoy reading your posts, and you seem to understand alot; more than many, including myself. however, this post is so wrong on so many levels.
corals are many times more heterotrophic in the wild than they are in our reef tanks. trying to reach nutrient levels that mimic the oceans, while possible would starve our corals in a reef tank. reefers would need to dump gallons of food in our tanks to even come close to the food that is available on the reefs.

what algae lives on the outer reef? you ask....all algaes, they get eaten by the miillons of animals. i'm doing a wc now...so we will pick this up latter.

 

[Reefin' Dude]

i enjoy reading your posts, and you seem to understand alot; more than many, including myself. however, this post is so wrong on so many levels.
corals are many times more heterotrophic in the wild than they are in our reef tanks. trying to reach nutrient levels that mimic the oceans, while possible would starve our corals in a reef tank. reefers would need to dump gallons of food in our tanks to even come close to the food that is available on the reefs.

what algae lives on the outer reef? you ask....all algaes, they get eaten by the miillons of animals. i'm doing a wc now...so we will pick this up latter.

then dump gallons of food into the tank. it doesn't matter how much food you put in the tank if you can remove it as fast. that is all i am saying. we are so worried about nutrients we do not feed enough. we need to import and export material to match the trophic level we are trying to emulate.

I've always understood eutrophication to specifically refer to an increase in dissolved nutrients, usually inorganic N+P, and usually in a body of freshwater. In FW lakes, biomass often plays into the measurement of trophic state index (which is usually a measure of chlorophyll [algae], P, and turbidity), but I don't think that can be directly applied to SW systems or tanks. Coral reefs are able to support levels of biomass (and planktonic life) that far exceeds a eutrophic FW lake without any negative effects on biodiversity or dissolved oxygen. I'd argue that the same is true for our tanks. More life != eutrophication if a tank is well managed.

An increase in biomass does not necessarily come along with an increase in dissolved nutrients.

If nutrients are stored, bound, or utilized (as they are on a coral reef), then the degree to which nutrients must be exported relative to imports decreases proportionally. In other words, if imports </= exports + growth + sequestration, no eutrophication occurs. However, if imports > exports + growth + sequestration, levels of dissolved nutrients increase, resulting in a process akin to eutrophication. An increase in biomass is not deleterious to a system (and an increase in biodiversity is quite beneficial), provided that increase does not exceed the carrying capacity of the system in one way or another.

how is an increase in biodiversity beneficial? what are all of those other mouths doing besides creating more waste? every living thing takes in nutrients and then produces wastes. the only way that more nutrients would be bound to this biodiversity is if the biodiversity population is always increasing. if not, than the those nutrients bound in those organisms becomes free again. if there are more of these organisms, than there must be more waste? what is all of this waste doing for our systems that is beneficial? feeding more organisms? to what end? at some point something has to give. the more biodiversity you have the more razors edge the system becomes. any little chance can cause a collapse in one of those organisms releasing the bound nutrients that they contained.

G~

 

[LobsterOfJustice]

I used a refugium (er, tried to) when I first got in the hobby as that was "the way to set up a tank." Never got the algae to grow after trying for four years. I tried high flow, low flow, high light, low light, 24 hour light, 12 hour light, shallow sand, deep sand, no sand... never got a proper functioning refugium where you harvest algae every few weeks as nutrient export. For nutrient export, IMO it's easier, less space, and more effective to just have high flow in the display and a big honkin skimmer in the sump.

As far as pod production, I've never been convinced a refugium does much... the adults are generally going to stay in the refugium. In my current setup I've just got a bunch of LR rubble in my return chamber and between the baffles of my sump... I plan on removing this when the tank gets a little more established.

My time in the hobby has lead me to believe that there are essentially two methodologies, both of which work: process the waste and nutrients, or remove the waste before they break down. Refugiums and DSBs are part of the process the waste methodology, and barebottom and ULNS tanks follow the remove the waste methodology. It's worth noting that you don't have to have a BB tank to follow the remove the waste methodology. What I have found does not work however is mixing the methodologies. I never had a proper functioning refugium in my old setup because I had 70x turnover and a skimmer rated for 4x the tank volume and there werent any nutrients leftover for the algae to grow.

I don't know which system is "better," but current methods of "remove the waste" can definitely result in a lower nutrient tank than "process the waste".

 

[GroktheCube]

how is an increase in biodiversity beneficial? what are all of those other mouths doing besides creating more waste? every living thing takes in nutrients and then produces wastes. the only way that more nutrients would be bound to this biodiversity is if the biodiversity population is always increasing. if not, than the those nutrients bound in those organisms becomes free again. if there are more of these organisms, than there must be more waste? what is all of this waste doing for our systems that is beneficial? feeding more organisms? to what end? at some point something has to give. the more biodiversity you have the more razors edge the system becomes. any little chance can cause a collapse in one of those organisms releasing the bound nutrients that they contained.

G~

There are four major benefits to biodiversity in a closed system in my opinion, though one of them is a bit subjective. First and foremost, increased stability of the system as a whole is one of the most important advantages of biodiversity. Having multiple species filling a given niche and having more niches filled means that a bad event is less likely to trigger total collapse. If you have multiple species filling a niche, and all of the members of one of those species suddenly die, there will be other critters ready to pick up the slack. Additionally in the event of conditions suddenly changing (ie: a large nem getting diced by a PH), having a more mouths in the tank means more animals to consume that organic matter before it begins rotting.

More mouths also isn't quite as simple as more mouths = more waste. When you have a large number of trophic niches filled (from primary producers all the way down), nutrient efficiency is effectively improved. Every time an organism consumes something, be it algae taking up inorganic N and P, a tang eating the algae, or a pod eating poop, more energy and nutrients are retained by the organism than excreted. No process is 100% efficient, so there will always be some nutrients left over as true waste, but having more species at different trophic levels (meaning distance from primary producers, not TSI) means that any given input will result in less total "waste" that needs to be exported.

Another benefit of increased biodiversity is a nutritional one. There is substantial variation between species in terms of macro- and micronutrient makeup, including differences in amino acid and fatty acid makeup and concentration. Often, heterotrophs that come from an ecosystem where there is tremendous diversity in food items consumed require a larger variety of micronutrients that are indispensable than those from an environment where meal choice is less of a luxury. In other words, having a greater variety of food on the table means that our inverts and dish are more likely to get all of their EAAs, EFAs, and vitamins. This tends to lead to healthier, more resilient, faster growing livestock, as even a small deficit in a single indispensable nutrient will have a deleterious impact.

Finally, there is the simple and subjective matter of aesthetics. As I stated earlier, one of my primary motivations for building a large fuge is because I think it looks cool. I've been fascinated by marine ecosystems and the complex interspecies relationships found therein since I was a little kid. Being able to see a greater variety of life and more different types of biotopes holds a lot of appeal for me. That said, I can also spend hours staring at a square foot of LR, waiting to see what crawls out, so I may be a special case

 

[GroktheCube]

I used a refugium (er, tried to) when I first got in the hobby as that was "the way to set up a tank." Never got the algae to grow after trying for four years. I tried high flow, low flow, high light, low light, 24 hour light, 12 hour light, shallow sand, deep sand, no sand... never got a proper functioning refugium where you harvest algae every few weeks as nutrient export. For nutrient export, IMO it's easier, less space, and more effective to just have high flow in the display and a big honkin skimmer in the sump.

As far as pod production, I've never been convinced a refugium does much... the adults are generally going to stay in the refugium. In my current setup I've just got a bunch of LR rubble in my return chamber and between the baffles of my sump... I plan on removing this when the tank gets a little more established.

My time in the hobby has lead me to believe that there are essentially two methodologies, both of which work: process the waste and nutrients, or remove the waste before they break down. Refugiums and DSBs are part of the process the waste methodology, and barebottom and ULNS tanks follow the remove the waste methodology. It's worth noting that you don't have to have a BB tank to follow the remove the waste methodology. What I have found does not work however is mixing the methodologies. I never had a proper functioning refugium in my old setup because I had 70x turnover and a skimmer rated for 4x the tank volume and there werent any nutrients leftover for the algae to grow.

I don't know which system is "better," but current methods of "remove the waste" can definitely result in a lower nutrient tank than "process the waste".

IMHO, its possible to have the best of both worlds, one need not limit themselves to just one "method". I have a bit over 7500gph of water movement in my 120, including a 1.5" standing wave. I also have over 30" of active overflow, a very large fairly low velocity sump designed to help settle detritus, and an over rated skimmer. I also have a deepish sand bed in the DT, and I'm setting up a fuge with nearly 1/4th system volume.

The way I see it, I have all my bases covered

 

[CHSUB]

finished wc..... ulns. i know what it means, it is a new term in reef keeping that is worthless. i see people say they have ulns using API test kits. i just received 400 gallons of NSW from Halover cut in miami and my "highly" sensitive tests kits read 0.00 on both NO3(salifert) and PO4(photometer); and i know this water has many times higher concentations of both than ocean water on the reefs....... fugs are a great tool, period. if algae does not grow in your tank something is wrong, because if the algae dies so do your corals. i run a fug, and harvest algae once a month or so. my dt has not one spect of algae beside coralline ALGAE! two methodologies of reef keeping?????

"My time in the hobby has lead me to believe that there are essentially two methodologies, both of which work: process the waste and nutrients, or remove the waste before they break down"

i find this one of the most ridiculous statements i have read today....one method involves removal of waste, i guess. the other just lets it stew, i think?

 

[vair]

Fantastic thread! Thanks for the great read, very interestering.... More.

 

[DeepThought]

You can not convince me that starving my corals is good for them.

I'm not really sure you understand Ecology and Biology...

Sure, we should emulate the ocean, to an extent, in our tanks. However, on coral reefs in the wild, what they are getting is food with a low phosphate environment. They are getting their daily intake of phosphate through the ingestion of food. In our systems, we want to decrease the amount of waste, but also have a way to increase the amount of food. The only way to do that naturally is to increase biodiversity and those mouths, once again. The more mouths to feed, the more food you can feed your tank. The more ways you have of exporting decomposed nitrate and phosphate - IE skimmer or even by macroalgae, the better.

I don't see two separate spectrums of the hobby. I see skimmers and fuges working together to accomplish two separate goals. Skimmers simply remove FOOD from the water before a coral has a chance to consume it so that it doesn't turn in to nitrate and phosphate. Algae grows by the decomposition and waste products of all those mouths that we want to feed.

No one should starve their corals, but no one should overfeed their tanks either. You really do have to find that happy balance. We can not replicate mother nature in our closed system aquariums - you are trying to reach a goal that no one can attain, so your understanding of the natural biota of the ocean may be correct, but your theories and explanations of the hobby are wrong. As another member said, put the book down and actually pay attention to your tank.

Lets say this... you start a system that is bare bottom, with dead, bleached, acid bathed base rock and artificial sea water. You replicate the oceans currents, and your give your tank enough light to sustain a variety of corals. Soft corals, LPS corals, NPS corals and SPS corals. Now, lets say you don't have any fish in this system at all, and you do not feed your tank anything at all. No zooplankton, no phytoplankton... but you keep doing water changes with purified NSW, which contains no free floating organisms and a phosphate level of 0.009 or lower, with the same corrosponding nitrate level. According to you, soft corals, NPS corals, and LPS corals will probably die. SPS corals will thrive because all they need is light and a miniscule amount of phosphate. Is this what you are saying? Because, if it is,... I don't want that kind of system. I want a system that will be able to cultivate and grow all different varieties of corals, and be able to sustain genetic biodiversity through time. I don't want some freakish experiment in my livingroom, I want a thriving ecosystem.

By the way, I see in your signature that your tank info is "a sad story." .... now I don't really have to wonder why about that one, do I?

 

[CHSUB]

You can not convince me that starving my corals is good for them.

I'm not really sure you understand Ecology and Biology...

Sure, we should emulate the ocean, to an extent, in our tanks. However, on coral reefs in the wild, what they are getting is food with a low phosphate environment. They are getting their daily intake of phosphate through the ingestion of food. In our systems, we want to decrease the amount of waste, but also have a way to increase the amount of food. The only way to do that naturally is to increase biodiversity and those mouths, once again. The more mouths to feed, the more food you can feed your tank. The more ways you have of exporting decomposed nitrate and phosphate - IE skimmer or even by macroalgae, the better.

I don't see two separate spectrums of the hobby. I see skimmers and fuges working together to accomplish two separate goals. Skimmers simply remove FOOD from the water before a coral has a chance to consume it so that it doesn't turn in to nitrate and phosphate. Algae grows by the decomposition and waste products of all those mouths that we want to feed.

No one should starve their corals, but no one should overfeed their tanks either. You really do have to find that happy balance. We can not replicate mother nature in our closed system aquariums - you are trying to reach a goal that no one can attain, so your understanding of the natural biota of the ocean may be correct, but your theories and explanations of the hobby are wrong. As another member said, put the book down and actually pay attention to your tank.

Lets say this... you start a system that is bare bottom, with dead, bleached, acid bathed base rock and artificial sea water. You replicate the oceans currents, and your give your tank enough light to sustain a variety of corals. Soft corals, LPS corals, NPS corals and SPS corals. Now, lets say you don't have any fish in this system at all, and you do not feed your tank anything at all. No zooplankton, no phytoplankton... but you keep doing water changes with purified NSW, which contains no free floating organisms and a phosphate level of 0.009 or lower, with the same corrosponding nitrate level. According to you, soft corals, NPS corals, and LPS corals will probably die. SPS corals will thrive because all they need is light and a miniscule amount of phosphate. Is this what you are saying? Because, if it is,... I don't want that kind of system. I want a system that will be able to cultivate and grow all different varieties of corals, and be able to sustain genetic biodiversity through time. I don't want some freakish experiment in my livingroom, I want a thriving ecosystem.

By the way, I see in your signature that your tank info is "a sad story." .... now I don't really have to wonder why about that one, do I?

outstanding!!!!!

fyi.

here is my fug, after harvest!



my skimmer, no gfo.!



my dt, no algae, but coralline!

 

[rlpardue]

how many of those points do not deal with covering up the affects of eutrophication though?

again the more life, the more nutrients needed to feed the life, and the more wastes they produce. for what reason?
G~

Because the life is interesting lol! :debi:

I think you're misunderstanding the reason why most people keep reef tanks. The reason is that it is INTERESTING. Not so that I can grow SPS in a petri dish, although I won't knock anybody for doing so. I'm just saying it's not the reason I keep a reef tank.

 

[gcline87]

Systems have thrived with no sump or refugium at all and little to no maintenance. Other systems have performed equally well with a refugium and the whole nine yards. To use Mr. Salwater TV's phrase "know your tanks personality" I think is very appropriate. There is no hard and fast answer to the refugium question, and its important to know what works for your tank. ps2cho, I think if you want to try out a refugium go for it. Test your tanks levels to have an empirical base for how well your tank is doing. I like reef dude's point of watching algae to know how your phosphate and nitrate levels are doing. One of the most important "maintenance tasks" we have as reefers is to simply watch our tanks so that we can sense when something is awry. rlpardue, I think you summarize some of the finest qualities of having a refugium, and it's the job of the reefer to decide what works for them. I plan on adding a mandarin goby, and for that reason will use a refugium to grow copepods. ps2cho, I would encourage you to identify your specific goal of adding a refugium and try your tank with and without one. Some people on this forum have shown refgiums to have little effect on their tanks health, in which case its just easier to do away with it all together. Others have demonstrated quantifiable benefits. Good luck.

 

[MrClam]

Fantastic information provided reefin, always nice to see hard science. Obviously strong opinions on refuge topic on both sides, and good debate to move the hobby forward.

To the OP I will speak to the benefits of a fuge in respects to fish, not corals, as most people here have been talking exclusively about corals. Some fish, such as mandarins sea horses and some wrasses, have a digestive physiology that relies on the presence of microfauna in constant supply. A properly designed fuge can help maintain the population of these microfauna in order to supply these fish with the proper diet to thrive. These fish will not do well in an oligotrophic environment.

 

[Reefin' Dude]

Because the life is interesting lol! :debi:

I think you're misunderstanding the reason why most people keep reef tanks. The reason is that it is INTERESTING. Not so that I can grow SPS in a petri dish, although I won't knock anybody for doing so. I'm just saying it's not the reason I keep a reef tank.

i think you all are missing my points. where did i say a petri dish? our systems are bacterial driven. it is not going to be a petri dish. all i am saying is limit the amount of bacteria by keeping the amount of available nutrients for them under control. all of those ATS/live sumps/hobby refugiums are all about taking out nutrients AFTER the bacteria have converted them into a form that they can use. just design the tank to maintain the amount of waste necessary to maintain the organisms you would like to keep. that is all. you can either have a BB and sweep everything into a skimmer or out through the siphon. if you want DSB, then you have to deal with the limited amount of binding sites on the calcium carbonate in the substrate, and replace it/aggressively clean it regularly (this can be years, but it will need to be done). there can be a mix of each. the point is that phosphates have to be removed.

IMHO, its possible to have the best of both worlds, one need not limit themselves to just one "method". I have a bit over 7500gph of water movement in my 120, including a 1.5" standing wave. I also have over 30" of active overflow, a very large fairly low velocity sump designed to help settle detritus, and an over rated skimmer. I also have a deepish sand bed in the DT, and I'm setting up a fuge with nearly 1/4th system volume.

The way I see it, I have all my bases covered

it is all about putting your phosphate eggs in the biggest phosphate sink you got. the deepish DSB. you can do any combination you may want. again you can siphon it all out, or sweep it into the substrate until the binding sites are full and the bacteria have chocked themselves out of resources, then replace or reset the substrate. again the point is that phosphates have to be removed. substrates are fantastic at migrating nutrients downwards. the unfortunate part is that our tanks have a bottom.

There are four major benefits to biodiversity in a closed system in my opinion, though one of them is a bit subjective. First and foremost, increased stability of the system as a whole is one of the most important advantages of biodiversity. Having multiple species filling a given niche and having more niches filled means that a bad event is less likely to trigger total collapse. If you have multiple species filling a niche, and all of the members of one of those species suddenly die, there will be other critters ready to pick up the slack. Additionally in the event of conditions suddenly changing (ie: a large nem getting diced by a PH), having a more mouths in the tank means more animals to consume that organic matter before it begins rotting.

why have these given niches? that is the point. just think through what everything is doing in our systems and then say why? what slack are these other organisms taking up? the eating of other poo? why is the poo there anyway? just remove it, then there is no reason to worry about having other organisms eating it or taking up their slack if their population crashes because of who knows what.

More mouths also isn't quite as simple as more mouths = more waste. When you have a large number of trophic niches filled (from primary producers all the way down), nutrient efficiency is effectively improved. Every time an organism consumes something, be it algae taking up inorganic N and P, a tang eating the algae, or a pod eating poop, more energy and nutrients are retained by the organism than excreted. No process is 100% efficient, so there will always be some nutrients left over as true waste, but having more species at different trophic levels (meaning distance from primary producers, not TSI) means that any given input will result in less total "waste" that needs to be exported.

why is it not that simple? the more people in a city the more crap that needs to be removed from their eating? it doesn't matter how efficient they are, the P is still there, that is the point. it doesn't matter how many organisms have transferred the P, it is still there. no P stays still. it is always in motion. even in a living organism. the P is used for energy production. the whole ADP ATP thing. P is in constant motion and being transferred from inorganic to organic and back again.

Another benefit of increased biodiversity is a nutritional one. There is substantial variation between species in terms of macro- and micronutrient makeup, including differences in amino acid and fatty acid makeup and concentration. Often, heterotrophs that come from an ecosystem where there is tremendous diversity in food items consumed require a larger variety of micronutrients that are indispensable than those from an environment where meal choice is less of a luxury. In other words, having a greater variety of food on the table means that our inverts and dish are more likely to get all of their EAAs, EFAs, and vitamins. This tends to lead to healthier, more resilient, faster growing livestock, as even a small deficit in a single indispensable nutrient will have a deleterious impact.

this is a valid point, if we knew that what the corals could be feeding on were these amino acids....... that the biodiversity in our systems is producing. i could totally believe this for those keeping the more eutrophic environment organisms such as softies, but for those organisms that are in oligotrophic environment i am not sure this will hold as true. their is very little organics in the oligotrophic environment except for that which is organically bound in the form of plankton. i would suggest anybody keeping a softie tank to use a substrate just for the reasons you give.

Finally, there is the simple and subjective matter of aesthetics. As I stated earlier, one of my primary motivations for building a large fuge is because I think it looks cool. I've been fascinated by marine ecosystems and the complex interspecies relationships found therein since I was a little kid. Being able to see a greater variety of life and more different types of biotopes holds a lot of appeal for me. That said, I can also spend hours staring at a square foot of LR, waiting to see what crawls out, so I may be a special case

absolutely there are all kinds of fantastic biotopes out there. the more biotopes we try and put into a single system the more compromised it is for all of the organisms involved. look at any picture of a reef. now put your size aquarium in scale into that picture. how many biotopes can you fit in the tank? these corals we keep have evolved to niche environments. why do WE think they are all the same niche environment?

You can not convince me that starving my corals is good for them.

I'm not really sure you understand Ecology and Biology...

Sure, we should emulate the ocean, to an extent, in our tanks. However, on coral reefs in the wild, what they are getting is food with a low phosphate environment. They are getting their daily intake of phosphate through the ingestion of food. In our systems, we want to decrease the amount of waste, but also have a way to increase the amount of food. The only way to do that naturally is to increase biodiversity and those mouths, once again. The more mouths to feed, the more food you can feed your tank. The more ways you have of exporting decomposed nitrate and phosphate - IE skimmer or even by macroalgae, the better.

I don't see two separate spectrums of the hobby. I see skimmers and fuges working together to accomplish two separate goals. Skimmers simply remove FOOD from the water before a coral has a chance to consume it so that it doesn't turn in to nitrate and phosphate. Algae grows by the decomposition and waste products of all those mouths that we want to feed.

No one should starve their corals, but no one should overfeed their tanks either. You really do have to find that happy balance. We can not replicate mother nature in our closed system aquariums - you are trying to reach a goal that no one can attain, so your understanding of the natural biota of the ocean may be correct, but your theories and explanations of the hobby are wrong. As another member said, put the book down and actually pay attention to your tank.

Lets say this... you start a system that is bare bottom, with dead, bleached, acid bathed base rock and artificial sea water. You replicate the oceans currents, and your give your tank enough light to sustain a variety of corals. Soft corals, LPS corals, NPS corals and SPS corals. Now, lets say you don't have any fish in this system at all, and you do not feed your tank anything at all. No zooplankton, no phytoplankton... but you keep doing water changes with purified NSW, which contains no free floating organisms and a phosphate level of 0.009 or lower, with the same corrosponding nitrate level. According to you, soft corals, NPS corals, and LPS corals will probably die. SPS corals will thrive because all they need is light and a miniscule amount of phosphate. Is this what you are saying? Because, if it is,... I don't want that kind of system. I want a system that will be able to cultivate and grow all different varieties of corals, and be able to sustain genetic biodiversity through time. I don't want some freakish experiment in my livingroom, I want a thriving ecosystem.

By the way, I see in your signature that your tank info is "a sad story." .... now I don't really have to wonder why about that one, do I?

where have i ever said anything about starving corals? i fed my tank 5 times a day. three during daylight hour and twice at night. i put a lot of food into my tanks. i am a firm believer in feeding, not limiting feeding because of the fear of nutrient build up. some food for thought; if a substrate actually processed nutrients the way were told, then why would we worry about nutrient build up and all? why would we warn people to feed sparingly? where is that disconnect where what we have been told and what really happens not put together? i fed blender mush and the store bought equivalent. i would remove 2 liters of skimmate a day. my once a week water changes were only big enough to remove the detritus that had accumulated in the system since the last water change. in general my water changes were only 10g. that is all of the maintenance i did. i could see all of the detritus and got rid of it. i was not in fear of nutrients. i was on top of all of them. this system may not be fore everyone, but it can be done quite easily and we do not need to live in fear of phosphates, and we do not need to all of the equipment needed to control phosphates if we know how phosphates behave in our systems.

G~

 

[sawcreatives]

As a follow up to this, do you think having a 120 gallon tank with fish like a mandarin and a wrasse would have enough pods to sustain their health?

I don't think most fuges would be enough to help out so much chemically with the health of the tank, but even 10 gallons dedicated to growing pods can really help feed the system, no?

 

[LobsterOfJustice]

I've just never seen any evidence or data to show that a refugium actually helps with pod production. I mean think about it, they live on the rocks and sand, that's where they are going to stay. They aren't planktonic, they wont just get accidentally whisked over the overflow in any major numbers.

I'm all for biodiversity and a healthy tank. I'm just not sure a refugium is necessary for that. Anything living in the refugium can live in the DT, it's just going to be a lower numbers, only come out at night, and maybe live deeper in the rockwork. And IMO its very easy for a refugium to do more harm than good and become a detritus trap.

 

[Aquatron]

I would say YAy to a hobbiest who is willing to research why a refugium was created in the first place. Then with that understanding he/she could then set out to build a true working refugium for the system they are putting together.
I would say Nay for all others.
There is only one very easy way to tell if you have set up a true "WORKING REFUGIUM"
Your fish in your DT will show you if its working and how well...........if your fish do not dart to your outlet's off and on 24/7 you do not have a true working refugium.

 

[GroktheCube]

why have these given niches? that is the point. just think through what everything is doing in our systems and then say why? what slack are these other organisms taking up? the eating of other poo? why is the poo there anyway? just remove it, then there is no reason to worry about having other organisms eating it or taking up their slack if their population crashes because of who knows what.



why is it not that simple? the more people in a city the more crap that needs to be removed from their eating? it doesn't matter how efficient they are, the P is still there, that is the point. it doesn't matter how many organisms have transferred the P, it is still there. no P stays still. it is always in motion. even in a living organism. the P is used for energy production. the whole ADP ATP thing. P is in constant motion and being transferred from inorganic to organic and back again.

Let me put it this way. Only a percentage of what any given organism takes in will be utilized, a portion of it will always be waste.

Let us concoct a hypothetical example.
Animal 1 is able to utilize 80% of food item A, the remainder is excreted as waste.
Animal 2 is able to utilize 80% of animal 1's waste, the remainder is excreted.
Animal 3 is able to utilize 50% of animal 2's waste, the remainder is excreted.

Assuming we only have 3 trophic levels in this example (there are usually far more), 100 units of nitrogen in food item A end up as 2 units of waste nitrogen that will likely dissolve. If we're talking about nitrogen, these figures are even rather conservative. Animal proteins usually have a PER over 90. Rather than ending up with 20 units of waste to be removed, we have instead allowed 18 units to transformed into potentially useful biomass.

The same holds true for phosphate. The more life in the tank, the greater the potential for a given unit of P to be utilized. That P, then bound in that organism, has the potential to then end up as food for one of the organisms that we were originally feeding directly.

this is a valid point, if we knew that what the corals could be feeding on were these amino acids....... that the biodiversity in our systems is producing.

Given most corals have somewhat limited ability to utilize dissolved N, amino acids from food items are very important.

i could totally believe this for those keeping the more eutrophic environment organisms such as softies, but for those organisms that are in oligotrophic environment i am not sure this will hold as true. their is very little organics in the oligotrophic environment except for that which is organically bound in the form of plankton. i would suggest anybody keeping a softie tank to use a substrate just for the reasons you give.

The "oligotrophic environment" described (I assume you mean a coral reef) has FAR more food in the water than we could ever provide in our tanks. For corals in the wild, the vast majority of their macro and micronutrient needs, with the exception of carbohydrates, are acquired via heterotrophy rather than autotrophy. Though coral reefs are sometimes described as oligotrophic, they bare absolutely no resemblance to the freshwater bodies that term is most frequently applied to. They are sites of exceptionally high levels of primary production, have extreme density of life, and the water is filled with plankton.

The point of a system designed for plankton production is to more accurately simulate the conditions found on a reef. More opportunities are there to convert dissolved nutrients into planktonic life and shed epiphytic material that is nutritionally useful to corals. Rather than being "nutrient export" as it is often described, it is a form of nutrient recycling. You can get more bang for your proverbial buck by turning waste into food, and encourage increased heterotrophy by corals to more accurately simulate the natural environment.

absolutely there are all kinds of fantastic biotopes out there. the more biotopes we try and put into a single system the more compromised it is for all of the organisms involved. look at any picture of a reef. now put your size aquarium in scale into that picture. how many biotopes can you fit in the tank? these corals we keep have evolved to niche environments. why do WE think they are all the same niche environment?

That is the point of inline refugia. It allows the creation of a separate biotope plumbed into the same system, allowing for a more accurate representation of both in the home.