What is a refugium?

[wombat]

Have you ever tried "larger" nano or large tank without a skimmer? Can you explain how a tank without a skimmer is more complex for a new person?

 

Yes. I would not suggest anybody try it for their first marine tank. IMO the most difficult challenge for new tank owners is managing water quality. A device that removes, rather than traps and nitrifies, waste before it has the chance to mineralize to N and P seems to be exactly the type of thing that would help, not hinder a novice aquarist. Worst case scenario for a skimmer, if it is designed and/or implemented improperly, is that it is a waste of money, but it will still help aerate and move the water. Can you think of a situation where adding a skimmer will have negative consequences for a tank? Worst case scenario for a refugium, if it is designed or implemented improperly, is that it traps detritus and becomes a net producer of N and P.

 

Here I'm still in the nano arena. I don't question that the fish you listed could thrive in a larger tank without a refugium or, for some like the mandarin, even direct feedings. For the record, I don't have a refugium because I'm trying to set up a macroalgae/SPS tank. I am not claiming that refugiums, especially those that are proportionately small to their display tanks, are going to some sort of food factory. However, for small fish that normally eat pods (of which most nano fish are included), the addition of a refugium provides a small and constant source of supplementary nutrition between the owner's feedings.

 

So you feel their benefit is in providing a food source to the aquarium? Every beginner's fish that I can think of will do absolutely fine with 1-2 direct feedings a day. If it won't, it is not a beginner's fish. Sure, a refugium will help, but do you think a beginner's largest concern should be water quality or fish nutrition? If given the choice between adding a refugium OR a skimmer (but not both) the choice seems really clear to me.

[Mr. Fosi]

A device that removes, rather than traps and nitrifies, waste before it has the chance to mineralize to N and P seems to be exactly the type of thing that would help, not hinder a novice aquarist.

 

While I would tend to agree...

 

Can you think of a situation where adding a skimmer will have negative consequences for a tank?

 

Yes I can. In my system (and others here on NR), having a skimmer on a small or mid-size tank can lead to so-called "overskimming".

 

I had a skimmer running on my system (thanks again, blue!) but soon after it got broken in and started really producing skimmate all my corals started looking like crap.

 

Now, you could argue that they were responding to an increase in water clarity, but this wasn't a response that manifested in 2-3 days, it took a couple weeks. At the end of the two weeks or so, everything was clamped up tighter than a drum. I yanked the skimmer and within another two weeks, things started to come back out. Again, this is circumstantial evidence but I have left the skimmer off and my softies have been been fine since.

 

 

Every beginner's fish that I can think of will do absolutely fine with 1-2 direct feedings a day. If it won't, it is not a beginner's fish.

 

Right, but I (and many others) do not feed this much. The most I have ever fed is once per day but generally it is more like once every three days. During the interim, I have seen my clowns prowling the rocks looking for inverts to eat.

 

If given the choice between adding a refugium OR a skimmer (but not both) the choice seems really clear to me.

 

That's your perspective.

 

From my end, money is always a concern and so my designs usually de-emphasize equipment and focus on using living organisms and waterchanges to manage the tank. The system I have now is the most gadgetized I have had; two pumps and a modded SCWD closed loop. My previous systems were driven by simple HOB filters and/or small powerheads. While those setups were not ideal, they were a way to for me to stay in the hobby despite being poor.

 

Now, of course someone will come by and make the oft repeated statement, "This isn't a cheap hobby; if you don't have cash, get out!" but think that is just wrong. If you don't focus on equipment and instead focus on getting quality rock and a quality light, you can get by without any major issues.

 

In my opinion, it isn't a bad idea to do both a refugium and a skimmer but as you have said, many of us are working where space is limited. If have the money and you plan to have livestock that require very clear, "clean" water, then a skimmer is must. If you are starting on a shoestring and you only want to keep some softies and maybe a couple LPS, then it is far from required.

[wombat]

While I would tend to agree...

 

 

 

Yes I can. In my system (and others here on NR), having a skimmer on a small or mid-size tank can lead to so-called "overskimming".

 

Here we go. Have you seen the article by Ken Feldman in last month's AA?

 

http://www.advancedaquarist.com/pdf/Advanc...ist-2009-01.pdf

 

Ken found that, regardless of skimmer brand or type, they all removed about 20-30% of DOC from aquarium water. It seems clear that there is a lot of stuff skimmers don't remove no matter how fancy they are, and if you want to sell me that "overskimming" is a real phenomenon I'll need some evidence of this type.

 

I had a skimmer running on my system (thanks again, blue!) but soon after it got broken in and started really producing skimmate all my corals started looking like crap.

 

Now, you could argue that they were responding to an increase in water clarity, but this wasn't a response that manifested in 2-3 days, it took a couple weeks. At the end of the two weeks or so, everything was clamped up tighter than a drum. I yanked the skimmer and within another two weeks, things started to come back out. Again, this is circumstantial evidence but I have left the skimmer off and my softies have been been fine since.

 

Post hoc erogo procter hoc. Corals get pale and clam up for a thousand different reasons.

 

Right, but I (and many others) do not feed this much. The most I have ever fed is once per day but generally it is more like once every three days. During the interim, I have seen my clowns prowling the rocks looking for inverts to eat.

 

And I'm sure they get a lot of nutrition from the food produced by the rocks inside the display. Didn't you agree with me on this point?

 

That's your perspective.

 

From my end, money is always a concern and so my designs usually de-emphasize equipment and focus on using living organisms and waterchanges to manage the tank. The system I have now is the most gadgetized I have had; two pumps and a modded SCWD closed loop. My previous systems were driven by simple HOB filters and/or small powerheads. While those setups were not ideal, they were a way to for me to stay in the hobby despite being poor.

 

Now, of course someone will come by and make the oft repeated statement, "This isn't a cheap hobby; if you don't have cash, get out!" but think that is just wrong. If you don't focus on equipment and instead focus on getting quality rock and a quality light, you can get by without any major issues.

 

In my opinion, it isn't a bad idea to do both a refugium and a skimmer but as you have said, many of us are working where space is limited. If have the money and you plan to have livestock that require very clear, "clean" water, then a skimmer is must. If you are starting on a shoestring and you only want to keep some softies and maybe a couple LPS, then it is far from required.

 

To that I would say if you're on a shoestring, a refugium probably isn't necessary either! It certainly uses more energy than a comparably sized skimmer. Store bought models are similarly priced for comparably sized units. I could DIY either one for about the same price. I have trouble understanding why you believe skimmers are for the people who aren't on a budget, but refugiums are...

[Mr. Fosi]

Corals get pale and clam up for a thousand different reasons.

 

Agreed, but it was all of them and it coincided with the responses coincided with the addition/subtraction of the skimmer. Conclusive? No, but enough for me keep the skimmer in the closet and out of the sump/refugium.

 

And I'm sure they get a lot of nutrition from the food produced by the rocks inside the display. Didn't you agree with me on this point?

 

Yes, but this is the common ground between you and lak. Not everyone feeds all the time so a supplemental food source is a good thing and having a refugium certainly doesn't hamper it.

 

To that I would say if you're on a shoestring, a refugium probably isn't necessary either!

 

Because 10g tanks are $8, the pump that runs the return (at least in my case) is the same size as would run a skimmer appropriate for my tank and the light that powers it is 20W, less than the pump. Siliconing baffles isn't exactly a complicated job that requires precision.

 

Not everyone can/will DIY a skimmer, though a person can make one that is very effective and consumes little energy. Most people, if they want a skimmer when they start, go out and buy one and quality skimmers aren't $8.

 

The more we go around the more I become convinced that this is simply a difference of opinion. I like refugiums and I see acceptable results in my tank without a skimmer (as do many, many others here). You like skimmers and see acceptable results without a refugium (as do others here). Conclusion? Pick the one that does what you want, fits your aesthetic, budget and goals or just use both.

 

Refugia and skimmers share some common benefits and have benefits unique to themselves.

[yardboy]

Here we go. Have you seen the article by Ken Feldman in last month's AA?

 

http://www.advancedaquarist.com/pdf/Advanc...ist-2009-01.pdf

 

Ken found that, regardless of skimmer brand or type, they all removed about 20-30% of DOC from aquarium water. It seems clear that there is a lot of stuff skimmers don't remove no matter how fancy they are, and if you want to sell me that "overskimming" is a real phenomenon I'll need some evidence of this type.

 

 

 

Post hoc erogo procter hoc. Corals get pale and clam up for a thousand different reasons.

 

I read and found Ken's article very informative, but remember, no one has a DOC skimmer, it's called a protein skimmer, and is used to remove excess protein from the water before it breaks down into DOC. While I agree with Isaac that a softie tank likely doesn't need a skimmer, and that a refugium can be quite a bit cheaper than a skimmer, my excperience has been that a skimmer is a very useful tool if you have a desire to raise the "colored sticks" that I am fond of but that Isaac isn't

On the other hand, Ken's article also pointed out that possibly activated carbon is more useful than a skimmer (because it removes DOC, not protein) Truthfully, the only corals I've seen adversely affected by DOC and/or phophates/nitrates are hard corals. softies can tolerate much nastier, to a limit, water quality. Interesting considering that they live side by side in the wild.

 

 

 

And I'm sure they get a lot of nutrition from the food produced by the rocks inside the display. Didn't you agree with me on this point?

 

 

 

To that I would say if you're on a shoestring, a refugium probably isn't necessary either! It certainly uses more energy than a comparably sized skimmer. Store bought models are similarly priced for comparably sized units. I could DIY either one for about the same price. I have trouble understanding why you believe skimmers are for the people who aren't on a budget, but refugiums are...

[wombat]

Because 10g tanks are $8, the pump that runs the return (at least in my case) is the same size as would run a skimmer appropriate for my tank and the light that powers it is 20W, less than the pump. Siliconing baffles isn't exactly a complicated job that requires precision.

 

Not everyone can/will DIY a skimmer, though a person can make one that is very effective and consumes little energy. Most people, if they want a skimmer when they start, go out and buy one and quality skimmers aren't $8.

 

Wait a second, are you suggesting the cost of the refugium is $8? What about the cost of the light, the cost of the baffles, the cost of the silicone, bulkhead (?)... And for people who don't have sumps? The associated plumbing alone would be more than that. Let's not forget the energy costs either, as even a pump driven skimmer for your tank would use far less than 20W.

 

You can make a skimmer for dirt cheap if you're on a budget. All you need is a vessel, an air pump, and an airstone. This is a skimmer I built for $13, plus the price of an air pump (another $10 if you don't have one laying around). Ghetto? Absolutely, please don't laugh too hard... But it worked, was not terribly sophisticated, and could be built in an hour or so with a drill and some sandpaper. This was for a 6g tank, but the concept could easily be sized up to a larger tank.

http://www.reefs.org/phpBB2/viewtopic.php?...asc&start=0

 

I think we have all been led to believe (myself included, no jabs intended) that skimmers need to be fancy contraptions which cost a good portion of a paycheck in order to do what they are intended to do.

 

The more we go around the more I become convinced that this is simply a difference of opinion. I like refugiums and I see acceptable results in my tank without a skimmer (as do many, many others here). You like skimmers and see acceptable results without a refugium (as do others here). Conclusion? Pick the one that does what you want, fits your aesthetic, budget and goals or just use both.

 

Refugia and skimmers share some common benefits and have benefits unique to themselves.

 

I somewhat disagree that what we've been discussing is a matter of opinion. What fish looks the neatest is an opinion. We are discussing things that could be quantified and tested in a carefully designed study. O2 contributions from photosynthesis vs. skimmers, for instance, or net N and P removal in a refugium vs. skimmer, or total food production of a refugium, etc. We would need to be really careful applying these to an aquarium setting, but I think they would be interesting to look at anyhow. I would be interested in doing such a thing if I wasn't so damn busy all the time! I do agree with your conclusion. In any case, I am glad we had this interesting discussion because I learned a few surprising things, although I'm sure the OP is confused as all hell...

 

Best,

Matt

 

PS This got me thinking...have you ever placed a plankton or baby brine shrimp net on the outflow of your refugium? Would it be possible to do on your setup? I'd be interested to see what it would catch after 24 hours. This goes for anyone, post pics, get it under a scope if you can...I'd be interested to see how much stuff (and what kind) is really overflowing into your display.

[Mr. Fosi]

Wait a second, are you suggesting the cost of the refugium is $8?

 

Well... It was for me. But that was because I had a bunch of junk laying around from other failed projects. If I had to buy it all just for that project, it probably would have been $50-60.

 

You can make a skimmer for dirt cheap if you're on a budget.

 

This is true but those dirt cheap skimmers take more babying. I really like wetworx's Remora Killer but I don't have the tools to do good acrylic cutting.

 

We are discussing things that could be quantified and tested in a carefully designed study. O2 contributions from photosynthesis vs. skimmers, for instance, or net N and P removal in a refugium vs. skimmer, or total food production of a refugium, etc.

 

Yes, they could be investigated (I could do the macro work fairly easily) but you would have to setup some pretty simplified systems to test any of those variables with any degree of confidence. Then you'd have people claim that the results didn't apply to the more complex whole system (even though they would be).

 

I could easily break off some sprigs of chaeto and pop them into our microrespirometry rig and get some data in an afternoon. It'd be gross primary productivity rate, O₂ concentrations and I could also do chaeto respiration by blacking the vials out. This would all be related to the light intensity that I was illuminating them with and the amount of chaeto in the cial, but I could do a range of intensities and see how the curve looked but I am sure it would be approximately a logistic-type curve with a dip at the really high intensities.

 

The more exhaustive study would take more than an afternoon but I could get some preliminary data fairly quick... Now if I could justify doing that in light of my other responsibilities. I still have a bunch of fluorescent lamps that people sent me who's spectrums I need to record but I just can't ever seem to find the time.

 

...have you ever placed a plankton or baby brine shrimp net on the outflow of your refugium? Would it be possible to do on your setup? I'd be interested to see what it would catch after 24 hours.

 

I have never done it, but I suppose I could but I don't think I would get anything interesting. When it comes down to it, I doubt the ability of my setup to act as a direct source of pods. I never thought it would be when I set it up, I wanted it mostly for it's sump capability. A place to dose, put carbon, stash a heater or a skimmer, etc...

 

Pods would have to be sucked up by the return pump without being busted to bits by the pressure gradient and then be spit out in the display above. That's why I regard my sump/refugium as a place to keep my heater, extra rubble, shells for the hermits and chaeto for nutrient export. Perhaps it is a source of juvenile pods but who knows?

[wombat]

Cool!

 

I really like wetworx's Remora Killer...

 

Link?

[Mr. Fosi]

http://www.nano-reef.com/forums/index.php?...8540&st=540

 

Ray sent me one of his old cheap ones and I never finished modding it to recirculate; it's still in my closet...

 

There are so many things I want to do but there is only so much time in the day!

[lakshwadeep]

Yes. I would not suggest anybody try it for their first marine tank. IMO the most difficult challenge for new tank owners is managing water quality. A device that removes, rather than traps and nitrifies, waste before it has the chance to mineralize to N and P seems to be exactly the type of thing that would help, not hinder a novice aquarist. Worst case scenario for a skimmer, if it is designed and/or implemented improperly, is that it is a waste of money, but it will still help aerate and move the water. Can you think of a situation where adding a skimmer will have negative consequences for a tank? Worst case scenario for a refugium, if it is designed or implemented improperly, is that it traps detritus and becomes a net producer of N and P.

 

I do not think that a skimmer would have negative consequences, but it is possible if the specific compounds being removed could have been utilized for growth of preferred organisms. For your worst case scenarios, it is hard to argue against you since refugiums are personalized constructions, while a skimmer is something you have invested in doing something unique (and hopefully doing it efficiently).

 

Here we go. Have you seen the article by Ken Feldman in last month's AA?

 

http://www.advancedaquarist.com/pdf/Advanc...ist-2009-01.pdf

 

Ken found that, regardless of skimmer brand or type, they all removed about 20-30% of DOC from aquarium water. It seems clear that there is a lot of stuff skimmers don't remove no matter how fancy they are, and if you want to sell me that "overskimming" is a real phenomenon I'll need some evidence of this type.

 

Is it not odd that even reliable skimmers only removes 20-30% DOC? To me, that sounds like an observation that does not support the necessity of even using a skimmer. Ironically, I was going to post that article's link before to support my argument. On a side note, I don't know what is the natural reef equivalent to a protein skimmer. The usefulness and suitability of live rock and water changes is obvious, but the most I've heard of natural equivalents to skimmers was waves producing froth at beaches.

 

So you feel their benefit is in providing a food source to the aquarium? Every beginner's fish that I can think of will do absolutely fine with 1-2 direct feedings a day. If it won't, it is not a beginner's fish. Sure, a refugium will help, but do you think a beginner's largest concern should be water quality or fish nutrition? If given the choice between adding a refugium OR a skimmer (but not both) the choice seems really clear to me.

 

I think Mr. Fosi has taken the words out of my mouth, or at least out of my keyboard. I will say that, at least in nano tanks, fish nutrition and water quality can be at loggerheads if the feeding schedule is such that it promotes nuisance algae growth.

 

Post hoc erogo procter hoc.

 

quidquid latine dictum sit, altum sonatur. (don't forget to do a "spell check" before posting latin phrases )

[wombat]

Is it not odd that even reliable skimmers only removes 20-30% DOC? To me, that sounds like an observation that does not support the necessity of even using a skimmer. Ironically, I was going to post that article's link before to support my argument. On a side note, I don't know what is the natural reef equivalent to a protein skimmer. The usefulness and suitability of live rock and water changes is obvious, but the most I've heard of natural equivalents to skimmers was waves producing froth at beaches.

 

It's troublesome, clearly. I think the fact that good old fashioned airstone driven skimmers were just as effective as the high end ones was surprising to everyone, even Ken. OTOH it seems clear that a lot of stuff is removed by skimmers...just look in the collection cup! I also think a lot more work of this type needs to be done on protein skimmers, as well as refugiums!

 

Interesting side note, although I think a lot of stuff happens in our tanks that don't have a "natural" equivalent. I think a lot of us (and I don't mean to single you out, it is a common theme on many subjects) get the idea that we are mimicking nature in our aquariums; people describe it as an "ecosystem", etc. or that they prefer to use more "natural" methods to filter their water. I think this is a misled and possibly narrow minded viewpoint if it limits new ideas and methodologies. I'll point to carbon dosing as an example of a somewhat interesting and possibly beneficial methodology that received a LOT of flak/doubt/naysaying in the beginning. And on the flip side, the very "natural" DSB method has proven problematic for some people...there are lots of examples.

 

 

quidquid latine dictum sit, altum sonatur. (don't forget to do a "spell check" before posting latin phrases )

 

That's what I get for trying to sound like I know what I'm talking about...

[Mr. Fosi]

Interesting side note, although I think a lot of stuff happens in our tanks that don't have a "natural" equivalent. I think a lot of us... get the idea that we are mimicking nature in our aquariums; people describe it as an "ecosystem", etc...

 

First, give me an example of some of the "stuff" that happens in our tanks that has no natural equivalent.

 

Second, the definition of "ecosystem" is: "a system formed by the interaction of a community of organisms with their physical environment" according to one of the definitions on Dictionary.com. I could look it Campbell & Reese, but what's the point? This broad definition is why the term is flexible enough to be used at virtually any scale. Our large intestine houses an ecosystem, our skin has an ecosystem, forests are ecosystems, etc...

 

Since our aquaria do house organisms that do interact with their environment, our tanks are in fact ecosystems. Now, whether they approximate "nature" is another question. First you need to define nature, then we need to quibble about the details; an argument that would likely lead us nowhere. I am happy to concede that the best that even the largest and most sophisticated systems can hope for is a rough approximation of a natural system, but I am not sure what that really matters.

 

We still have organisms that are common in "nature", they are still doing the same things they do in nature, the only things that can really be different from nature is the proportions at which you find these organisms. But if you want to make a judgment about what is "natural" and what isn't, you run into the problem that nature is variable. So looking at a tank that is overgrown with cyanobacteria it would be easy to say "That obviously is nothing like a natural system," until you find a part of a reef somewhere in the world where there is a preponderance of cyano mats, at least for a period of time.

 

Either way, if you wish to discard the paradigm of aquariums as ecosystems, then what alternate view do you propose and on what basis do you propose it?

[yardboy]

I get technoloically frustrated when I write a long reply and it turns into electronic vapor

One point that is missing here is that a skimmer removes protein, or undigested material from the water. It doesn't seem surprising to me that most of them can do that fairly quickly, so that only when you are feeding will you get the greatest removal. And face it, since we have no deep sea in our systems, we can never come close to emulating the ocean environment.

I find skimmers to be useful, within their limitations. I can also believe that activated carbon does a lot better job of removing DOC than a skimmer can. In my opinion, a refugium does precious little about removing DOC, but can help in removing nitrate and phosphate, though nitrate at least should be removed by the bacteria on the liverock, if it isn't and a refugium is needed, there's a bigger problem with nutrient build up. I do think that refugiums are also useful for diversity, not necessarily for stuff you can see like amphipods and copepods, but wit more microscopic stuff too, and for things that fish would eat so fast in the main tank that they'd never be able to establish a population of them otherwise. While there's not a great rush of pods out of the refugium on my nano system, I have observed pods come blowing out, and none the worse for wear after going through that maxijet, but then the jaws of a fish get them and......

I guess I'll say finally that different systems can use different things. I like sps corals, and feel that a skimmer is very useful at maintaining better quality water between water changes (certainly it doesn't replace WC's) but for zoanthids and softies, a skimmer isn't as needed, and WC's alone can do the job.

[Mr. Fosi]

I get technoloically frustrated when I write a long reply and it turns into electronic vapor

 

Write it in notepad first then c/p, safer that way.

 

One point that is missing here is that a skimmer removes protein, or undigested material from the water.

 

I took it as given that those engaged in this discussion already knew that.

 

I guess I'll say finally that different systems can use different things. I like sps corals, and feel that a skimmer is very useful at maintaining better quality water between water changes (certainly it doesn't replace WC's) but for zoanthids and softies, a skimmer isn't as needed, and WC's alone can do the job.

 

This has been my main point.

 

You don't really need either one on simple setups with hardy livestock. In reality, most of the systems I see here on NR fit that description.

[Mordoff]

Write it in notepad first then c/p, safer that way.

 

 

 

I took it as given that those engaged in this discussion already knew that.

 

 

 

This has been my main point.

 

You don't really need either one on simple setups with hardy livestock. In reality, most of the systems I see here on NR fit that description.

 

So if you have a skimmer does it mean that you dont have to do as many water changes?

[Mr. Fosi]

Sometimes yes and sometimes no. Depends on you think waterchanges are supposed to accomplish.

[smedge]

Here is something you guys haven't touched on yet.

 

It is my personal belief that skimmers remove not just DOC but also small particulate planktonic matter from the water column. Particulate matter that would otherwise be eaten by corals. I base this belief on experience with corals like Gonipora and Gorgonians in a skimmerless vs skimmed environment, and also by what I have observed in skimmate under a microscope. These days I never use mechanical filtration or skimming and constantly get great growth in things like gonipora with far less feeding than is typically recommended.

 

An algae bed in a fuge provides a place for organisms like this to establish themselves. Keeping the tank skimmerless and filterless allows those organisms to thrive in the water column where they are preyed on by corals. It's just a way more natural way of doing it than constantly straining and skimming your water column while you add food to the tank daily. I'm a firm proponent of the ideaology that less is more when it comes to saltwater tanks and corals. I really like to solve issues with biology as opposed to chemistry. I also stock sensibly.

[wombat]

First, give me an example of some of the "stuff" that happens in our tanks that has no natural equivalent.

 

Okay: GFO, lanthanum chloride, activated carbon, ozone, calcium hydroxide, sulfur denitrators, sand filters etc. etc...before you counter with "myself and others don't use any of that and our tanks look fine", I will say that at a large scale these are the most efficient and cost effective ways of accomplishing the same exact things we accomplish with good ole' natural water changes and refugiums--trying to maintain water quality that is as close to that found on a reef as possible. Here's the kicker--the animals don't seem to mind if it is accomplished in a very "natural" or very "artificial" way. Again, not suggesting that one is better than the other, just that the distinction is irrelevant.

 

Second, the definition of "ecosystem" is: "a system formed by the interaction of a community of organisms with their physical environment" according to one of the definitions on Dictionary.com. I could look it Campbell & Reese, but what's the point? This broad definition is why the term is flexible enough to be used at virtually any scale. Our large intestine houses an ecosystem, our skin has an ecosystem, forests are ecosystems, etc...

 

Sure, under that vague deinition you could say just about any group of animals, say a dog and a cat in your backyard, is an "ecosystem" too. Here's a definition I found on wikipedia (go figure):

 

"Any unit that includes all of the organisms (ie: the "community") in a given area interacting with the physical environment so that a flow of energy leads to clearly defined trophic structure, biotic diversity, and material cycles (ie: exchange of materials between living and nonliving parts) within the system is an ecosystem."

 

This clearly does not describe what is happening in most marine aquariums. We add a lot of material (calcium, alkalinity, food, water changes) and remove a lot as well (algae harvesting, mechanical filtering, water changes); without the constant human interference we would have a relatively quick breakdown of the system. The constant human (or artificial, un-natural, however) intervention is a beneficial thing in this context, no?

 

Since our aquaria do house organisms that do interact with their environment, our tanks are in fact ecosystems. Now, whether they approximate "nature" is another question. First you need to define nature, then we need to quibble about the details; an argument that would likely lead us nowhere. I am happy to concede that the best that even the largest and most sophisticated systems can hope for is a rough approximation of a natural system, but I am not sure what that really matters.

 

We still have organisms that are common in "nature", they are still doing the same things they do in nature, the only things that can really be different from nature is the proportions at which you find these organisms. But if you want to make a judgment about what is "natural" and what isn't, you run into the problem that nature is variable. So looking at a tank that is overgrown with cyanobacteria it would be easy to say "That obviously is nothing like a natural system," until you find a part of a reef somewhere in the world where there is a preponderance of cyano mats, at least for a period of time.

 

Either way, if you wish to discard the paradigm of aquariums as ecosystems, then what alternate view do you propose and on what basis do you propose it?

 

I don't think I'm in any position to do something as grand as define nature or discard paradigms--I'm really just typing out loud and enjoying the back and forth. I do think that when people tend to describe their aquariums as "naturally filtered" there is the notion that it's superior to other methods of filtration simply by being "natural". I think that's a warm and fuzzy concept but has little to do with reality.

[Biotoper]

I'll add my 5c to this discussion. I have been debating for a long time whether to get a skimmer - I don't want to DIY one and I can't really prove to myself that throwing down $100 for a good one will do anything for what I care about: softie/lps coral and anemone growth and vibrancy.

 

I'm a big fan of refugiums, mainly because I like to stare at mine about as much as my display. I have had a 20g set up with a ~20g sump for 3 years - lots of softies and BTA's, a little LPS, pair of ocellaris, one pep shrimp, some snails. The sump is just ~3" DSB, LR rubble, tons of macroalgae, and the return pump in a bucket - no baffles. I set it up primarily to have more water volume. I have never had a skimmer and I don't do frequent water changes - probably 10% every few months.

 

I have never had detectable nitrate or phosphate, except slightly at the beginning, so I can't prove that the refugium/algae scrubber is reducing nutrients more than the display lr/dsb is. The water has always been perfectly clear. The display is full of copepods (I have noticed a reduction in larger amphipods over the years - the ones with the curled backs - vs the ones on the glass that are still very abundant). The clowns don't really forage much for pods. I've never observed any macroscopic pods sent to the display by the return pump. The refugium may help boost the amount of microscopic fauna in the water column, for the corals. There's definitely lots more worms in the refugium sand than the display, and I get lots more sponges growing in the refugium.

 

I just personally love having a refugium and am not confident that adding a skimmer will have any benefit.

[Mr. Fosi]

One needs to be careful when using words like "natural" which is why I don't usually use it.

 

"Any unit that includes all of the organisms (ie: the "community") in a given area interacting with the physical environment so that a flow of energy leads to clearly defined trophic structure, biotic diversity, and material cycles (ie: exchange of materials between living and nonliving parts) within the system is an ecosystem."

 

Ok... But we see mineralization and the creation of organic matter, so it seems to me that this definition more firmly supports what we see in our tanks.

 

This clearly does not describe what is happening in most marine aquariums.

 

It most certainly does!

 

... without the constant human interference we would have a relatively quick breakdown of the system. The constant human (or artificial, un-natural, however) intervention is a beneficial thing in this context, no?

 

"Breakdown" is another loaded term. What you would see if you stopped doing anything in your tank would be a shift. I know why you say breakdown, but that is another perspective issue. The type of system you see in the tank that has broken down might easily be found deeper within a "natural" reef away from the surface.

 

When you start discussing ecology, questions of what "normal", "natural", "beneficial", "disturbed" and so forth becomes tricky because all those terms are relative. They require a reference point to be relevant and it is often very hard to identify the proper reference point.

 

I do think that when people tend to describe their aquariums as "naturally filtered" there is the notion that it's superior to other methods of filtration simply by being "natural". I think that's a warm and fuzzy concept but has little to do with reality.

 

I guess I don't really know what it "natural" and what isn't. What I do know is that I don't have any problems keeping my calc/alk in acceptable limits without dosing. I don't have a problem regulating my pH without dosing or additional equipment (unless you count the macro and light equipment). I also never feel as though I need to be careful about how much macro I use and it keeps doing it's job whether I am home or not.

 

Know what I mean?

[wombat]

One needs to be careful when using words like "natural" which is why I don't usually use it.

 

Agreed! So would you agree that assessing the effectiveness of a particular methodology or technique on that nebulous criteria ("it isn't natural", "a natural way of filtering") is erroneous?

[Mr. Fosi]

I agree that classifying one as more "natural" has little meaning and that assessing effectiveness based on that is not useful.

 

Doesn't change the fact that my macro is better for my softy tank than my skimmer was!

[firstchevalier]

For what it's worth, given we are taking an amount of the ocean so small comparatively to the original as to be immeasurable. Given the immense size of the original, i.e. the wide open oceans and seas, what we do in our tanks on an INDIVIDUAL basis should not be considered 'natural' in any sense of the term. I would submit the term 'effective' or 'not effective' is better to describe what we're going for given a specific setup.

 

Additionally, given the wide range of how people setup their tanks it is very, very difficult to say that one approach is the lock-solid only way of doing things. Ultimately, if it is 'effective' in your setup and not harmful to your organisms, then I say pursue it. If it is 'ineffective' I say discard it.

 

That's my opinion, we welcome yours...

[wombat]

I agree that classifying one as more "natural" has little meaning and that assessing effectiveness based on that is not useful.

 

Doesn't change the fact that my macro is better for my softy tank than my skimmer was!

 

Okay, and it also doesn't change the fact that the 2 nicest looking reef tanks in the world (IMHO), at Atlantis Marine World and Waikiki Aquarium, are both run with big fat skimmers, hardly a trace of macro, and certainly no dedicated refugium...

 

Double

[Scott Riemer]

Nicest reefs I've seen had macro and no skimmer. Oh wait, sorry, that was the ocean.