New System: Substrate vs Bare Bottom
- Thread starter riemannp
- Start date
Gary Majchrzak
Team RC
do we really need to compare open systems with closed systems?
Reefkeeping 101: reef aquariums aren't the ocean.
I've never seen an ocean in an aquarium either.
The deep sand bed arguments get acrimonius and philisophical very quickly. The Deep sand bed thread in the New to the Hobby forum(http://www.reefcentral.com/forums/showthread.php?t=1652103) does contain some good information about why and how they work and /or don't work and their limits. There are many corrections and arguments and theories in that thread that detract from it and obfuscate the information but it's buried in there. Every one has an opinion on sand beds it seems and there is little data on them although there is significant information on denitrification.
Sanbed discussions can be abrasive , shifting and heated ; staying clear of them is wise unless you bring a big sand(BS) shovel and a pail of water and a sieve to sort out any gems that may be there.
Personally, I prefer shallow beds of fine sand with pools of sand for wrasses and other fish that need them. I like the beachy look and reflective capacity of the white sand. I run heavy flow but will careful direction blowing is not an issue.
Don't get me wrong ,
I like 4+ inch sand beds and the animals they support including the micro fuana and worms, wrasses, jawfish, certain anemones, etc., but there are other options for denitrification and fish habitat and my primary focus is not on maintaining an undisturbed bed but the aquarium it supports.
Once it was clear to me that denitrification occurred in very shallow sediment or even bacterial mulm, deep beds and some of the hypothesized but unproven dos and don'ts and endless often acrimonious debate became less interesting .
In my opinion , the biggest misconceptions center on the dynamics in a deep bed and a lack of focus on the needs of the facultative heterotrophic denitrifying bacteria which the bed is supposed to support in a denitrifying application. A deep bed of sand can't support these bacteria in anaerobic denitrification unless there is enough water movement in the deeper areas to insure a hypoxic environment(low O2 with NO3) without going to an anoxic enivronment(no O2 and no NO3). The latter sets the stage for sulfate reducing bacteria and their byproduct , hydrogen sulfide when tidbits of organic carbon are present such as that in the heterotrophs that die in anoxic water which they themselves can create by exhausting the oxygen and NO3 if it's not replenished in their locale.
There also has to be a way for organic carbon to move into the bed since the heterotrophs need it along with a little phosphate and nitrogen. So it's a pretty delicate balance between the amounts the bacteria consume and the amounts provided which for the most part relies on benthic fuana to keep channels open and move some nutrients around.
While some diffusion, molecular equilibration , will occur in water , it's a pretty weak force in the bed and won't add much to the deeper areas of a sand bed. Advection ,upwelling caused when horizontal current encounters obstacles like rock work and causes a subsequent downward flow , is a bit better but still not strong enough to penetrate very deeply in much volume. Thus, it seems there is a need for a healthy live bed with organisms to keep it channeled and move some nutrients down.Keeping such a live bed will likely require periodic replensihment/replacement with live sand and enough food or animal waste to support the sand critters. Maintaining a balanced group of fuana and microfuana in the sand longterm may be quite hard to achieve in reality.
Then on top of all that clumping can occur from on /off bacterial activity and localized ph changes in the bed. Localized anoxic conditions and associated ph changes may also unbind some metals from refractory organics in an older bed .
There are many reports of deep sand bed failures from seasoned aquarists. Apparently, they can become clogged and ineffective or harmful without some efforts at methods to keep them healthy.
Unfortunately, there are a lot of anecdotes and opinions about methods but little in terms of actual practices and long term successes.There are a dearth of documented accounts of long term (beyond 5 years)effective sand beds, at least that I have been able to find, and no protocols for keeping them effective much longer other than vagueries about replenishment and benthic fuana,flow, depth ,grain size , optimal and banned cleanup crew members, etc.
I ran a deep sand bed for over 7 years; did some replenishment over the years ;probably could have done more, and; then siphoned most of it out after nitrates took off and it seemed to fail.
FWIW at this point I keep mostly shallow beds with some deeper pools of sand for wrasses and my pistol shrimp.I'll probably try another deep bed at some point since they are aesthetically pleasing to me and I enjoy the thought of all the activity in them even though I don't need one to have an adequate bio filter.
The deep sand bed arguments get acrimonius and philisophical very quickly. The Deep sand bed thread in the New to the Hobby forum(http://www.reefcentral.com/forums/showthread.php?t=1652103) does contain some good information about why and how they work and /or don't work and their limits. There are many corrections and arguments and theories in that thread that detract from it and obfuscate the information but it's buried in there. Every one has an opinion on sand beds it seems and there is little data on them although there is significant information on denitrification.
Sanbed discussions can be abrasive , shifting and heated ; staying clear of them is wise unless you bring a big sand(BS) shovel and a pail of water and a sieve to sort out any gems that may be there.
Personally, I prefer shallow beds of fine sand with pools of sand for wrasses and other fish that need them. I like the beachy look and reflective capacity of the white sand. I run heavy flow but will careful direction blowing is not an issue.
Don't get me wrong ,
I like 4+ inch sand beds and the animals they support including the micro fuana and worms, wrasses, jawfish, certain anemones, etc., but there are other options for denitrification and fish habitat and my primary focus is not on maintaining an undisturbed bed but the aquarium it supports.
Once it was clear to me that denitrification occurred in very shallow sediment or even bacterial mulm, deep beds and some of the hypothesized but unproven dos and don'ts and endless often acrimonious debate became less interesting .
In my opinion , the biggest misconceptions center on the dynamics in a deep bed and a lack of focus on the needs of the facultative heterotrophic denitrifying bacteria which the bed is supposed to support in a denitrifying application. A deep bed of sand can't support these bacteria in anaerobic denitrification unless there is enough water movement in the deeper areas to insure a hypoxic environment(low O2 with NO3) without going to an anoxic enivronment(no O2 and no NO3). The latter sets the stage for sulfate reducing bacteria and their byproduct , hydrogen sulfide when tidbits of organic carbon are present such as that in the heterotrophs that die in anoxic water which they themselves can create by exhausting the oxygen and NO3 if it's not replenished in their locale.
There also has to be a way for organic carbon to move into the bed since the heterotrophs need it along with a little phosphate and nitrogen. So it's a pretty delicate balance between the amounts the bacteria consume and the amounts provided which for the most part relies on benthic fuana to keep channels open and move some nutrients around.
While some diffusion, molecular equilibration , will occur in water , it's a pretty weak force in the bed and won't add much to the deeper areas of a sand bed. Advection ,upwelling caused when horizontal current encounters obstacles like rock work and causes a subsequent downward flow , is a bit better but still not strong enough to penetrate very deeply in much volume. Thus, it seems there is a need for a healthy live bed with organisms to keep it channeled and move some nutrients down.Keeping such a live bed will likely require periodic replensihment/replacement with live sand and enough food or animal waste to support the sand critters. Maintaining a balanced group of fuana and microfuana in the sand longterm may be quite hard to achieve in reality.
Then on top of all that clumping can occur from on /off bacterial activity and localized ph changes in the bed. Localized anoxic conditions and associated ph changes may also unbind some metals from refractory organics in an older bed .
There are many reports of deep sand bed failures from seasoned aquarists. Apparently, they can become clogged and ineffective or harmful without some efforts at methods to keep them healthy.
Unfortunately, there are a lot of anecdotes and opinions about methods but little in terms of actual practices and long term successes.There are a dearth of documented accounts of long term (beyond 5 years)effective sand beds, at least that I have been able to find, and no protocols for keeping them effective much longer other than vagueries about replenishment and benthic fuana,flow, depth ,grain size , optimal and banned cleanup crew members, etc.
I ran a deep sand bed for over 7 years; did some replenishment over the years ;probably could have done more, and; then siphoned most of it out after nitrates took off and it seemed to fail.
FWIW at this point I keep mostly shallow beds with some deeper pools of sand for wrasses and my pistol shrimp.I'll probably try another deep bed at some point since they are aesthetically pleasing to me and I enjoy the thought of all the activity in them even though I don't need one to have an adequate bio filter.
Let’s see if I can stir us up further, and kick this one up a notch! Enjoy!
1. Any given configuration has it’s risks and benefits; they are all different. Perfection, of course, should never be the goal.
2. Any reef system may have a certain “life”; BB or DSB; depending on husbandry; attention to maintenance and replentishment; simple fate; frequency of major events such a long power outage or ammonia spike; the occasional owners gross negligence of his/her system for a period of time; acts of God; etc. Given the great diversity , complexity, and even fragility of these systems, any given system may reach it’s “service live” at 5 years or 20 years.
3. The infamous “DSB vs SSB vs BB” debate of closed systems should be taken up in a marine biology or oceonography PH.D thesis. The industry deserves more data.
4. The subject matter experts in our field (Ron Shimek, Julian Sprung, etc) should be respected more on the forums for their work (texts) and should not be dismissed as “out of date”. For example, it’s surprising to see some links above in this thread not even recognized in the subsequent posts. I wish folks would point to expert narrative … and not necessary other threads …more to back up statements.
5. The information on blogs should be filtered heavily (albeit tremendously valuable information from those “in the trenches”)
6. Unless you truly feel you are an expert, try to resist the temptation of pretending to sound like an expert.
7. The use of scientific words should not be interpreted as better knowledge / better judgement.
1. Any given configuration has it’s risks and benefits; they are all different. Perfection, of course, should never be the goal.
2. Any reef system may have a certain “life”; BB or DSB; depending on husbandry; attention to maintenance and replentishment; simple fate; frequency of major events such a long power outage or ammonia spike; the occasional owners gross negligence of his/her system for a period of time; acts of God; etc. Given the great diversity , complexity, and even fragility of these systems, any given system may reach it’s “service live” at 5 years or 20 years.
3. The infamous “DSB vs SSB vs BB” debate of closed systems should be taken up in a marine biology or oceonography PH.D thesis. The industry deserves more data.
4. The subject matter experts in our field (Ron Shimek, Julian Sprung, etc) should be respected more on the forums for their work (texts) and should not be dismissed as “out of date”. For example, it’s surprising to see some links above in this thread not even recognized in the subsequent posts. I wish folks would point to expert narrative … and not necessary other threads …more to back up statements.
5. The information on blogs should be filtered heavily (albeit tremendously valuable information from those “in the trenches”)
6. Unless you truly feel you are an expert, try to resist the temptation of pretending to sound like an expert.
7. The use of scientific words should not be interpreted as better knowledge / better judgement.
Gary Majchrzak
Team RC
fwiw
fwiw
I've had personal contact with Ron and Julian.
These guys are my "heroes". Right up there with McCartney.
fwiw
I've had personal contact with Ron and Julian.
These guys are my "heroes". Right up there with McCartney.
I agree Dr Shimek, Julian Sprung , Eric Borneman , Randy Farely et alia have made and conitinue to make sifgnificant contirbutions to the hobby. I've read their works many times. Still, this is an evolving hobby and there really isn't a need to genuflect to the noted authors before every discussion or to view every discussion through a prism of someone's idea of what they actually said. Original thinking , experience, discussion and debate are good things ,imo. I also think scientific language is a fine way to express scientific information and ideas as long as the concepts are presented as clearly as possible , the language is applied accurately and fact and opinion are carefully distinguished.
Agreed. These days I tend to do shallow beds as opposed to DSBs, but I was one of the original DSB adopters back in '97 and ran it successfully on a number of tanks over several years. I tend to smaller tanks these days though and I dislike DSBs for those.
Lately I've been pondering a trick I've seen done in terrariums, where small pieces of bark or fiber or moss - or sand - are mixed together with clear aquarium silicon to form continuous, solid sheets which appear to be composed of the substance added to the silicon.
Working outside of the aquarium and NOT directly on the tank bottom, it ought to be possible to make a sand "sheet" this way which could be used in place of starboard. It would likely get covered in coralline given time, and would of course be absolutely useless for maintaining any actual sand dwelling organisms. But it would provide a sand look to a tank with too much flow for a real sandbed.
Angel*Fish
cats and large squashes
I didn't take it that way at all. I thought it was a reference to the problem that the vast majority of opinions given about dsb's are by people who haven't read Shimek's article or anything at all other than other posts made mostly by others who, like themselves, have also read nothing but forum posts.
If you go to other RC forums, it's mind blowing how many people don't have the slightest idea they must learn a few things in order to do a dsb. I see post after post asking, "how deep should my dsb be" -they get an answer and think they're good to go. My favorite is the dsb thread that goes, "I just added 4 inches of sand and 2 sandsifting stars -- is that enough or should I add a sand sifting goby?".
I've gradually come to the conclusion that dsb's should be labeled as an advanced thing or at least not for your first tank. It's seems to be too much of a learning curve for people who are still grappling with why they shouldn't add 10 fish all at once the day after the initial cycle.
Instead of a long 23 page argument about dsb's, what people starting a dsb need is a clear, concise comprehensive how-to. Followed by an explanation of why plus a devils advocate artilce. And why not throw in a link to a long 23 page argument about them. That doesn't matter probably, because rare is the person who reads through one of those - which is my point.
Gary Majchrzak
Team RC
I'm in agreement with many of you!
I'm in agreement with many of you!
misinformation about DSB's is extremely common.
the aesthetic appeal of a DSB/SSB/BB in a DT are subject to opinions but the function and husbandry of each is factual- although there doesn't seem to be a lot of posters to the boards that know the facts.
I cited Shimek simply because this thread's OP referred to his published works on DSB's- not because I agree with everything he's written
I'm in agreement with many of you!
misinformation about DSB's is extremely common.
the aesthetic appeal of a DSB/SSB/BB in a DT are subject to opinions but the function and husbandry of each is factual- although there doesn't seem to be a lot of posters to the boards that know the facts.
I cited Shimek simply because this thread's OP referred to his published works on DSB's- not because I agree with everything he's written
dogstar74
Premium Member
Been there, done that. Worked well. Just do a search for Faux Sandbed. You'll see many. We used Two part clear epoxy. The brand was Envirotex lite I think. I got it at michaels hobby store. I used this in my 20H for many years without any problems. But it does become encrusted, and when I went with my 10 gallon, I just went back to a shallow sand bed.
Marie, Gary
Yes , I agree there is a lot of misinformation about sand beds; lot's of echos too. Trouble seems to be most of these discussions devolve into personal interpretations of some portion of a writing by one of the" heros"(mine too btw) sometimes misrepresenting the facts which leads to a correction ;then to a defensive comment and maybe a personal attack and so on. Any real information is easily lost in this type of process.
Since many new folks have sand beds;many believe they are knowlegeable and eager to discuss them and often get bad information or contradictory information and theoretical argument instead of how to guidance since the how tos are almost always debated often by folks with no experience at all. The lack of data and/ or solid detailed anecdotal accounts of long term success sets the stage for endless argument .
As an example ,in one case a fellow firmly recommended a certain number of inches of seacucumber ,holothuria for x number of sqaure inches of sand bed.When I pointed out that this might deplete the bacteria in the bed and that toxicity and techniques for keeping holothurids should be discussed in such a recommendation , he dismissed those concerns as irrelevant out of hand, demanding I cite an expert. I did not bother, even though articles he had already cited by Borneman and Calfo included these caveats.
Gary and I have had many shared learning discussions over the years and I'd certainly listen to Gary's account of his experience long before I'd listen to someone else's interpretation of what Eric Borneman may have said.But I'd listen to Eric Borneman directly before I'd listen to Gary for most issues .
I can read a book or an article as can others as they choose.
I wan't to hear folk's experiences since anecdotal information has value to me and sharng experiences is a great way to learn. I think many get scared away for fear of ridicule, usually by someone who doesn't know very much but is all to willing to present personal opinion as fact.
Yes , I agree there is a lot of misinformation about sand beds; lot's of echos too. Trouble seems to be most of these discussions devolve into personal interpretations of some portion of a writing by one of the" heros"(mine too btw) sometimes misrepresenting the facts which leads to a correction ;then to a defensive comment and maybe a personal attack and so on. Any real information is easily lost in this type of process.
Since many new folks have sand beds;many believe they are knowlegeable and eager to discuss them and often get bad information or contradictory information and theoretical argument instead of how to guidance since the how tos are almost always debated often by folks with no experience at all. The lack of data and/ or solid detailed anecdotal accounts of long term success sets the stage for endless argument .
As an example ,in one case a fellow firmly recommended a certain number of inches of seacucumber ,holothuria for x number of sqaure inches of sand bed.When I pointed out that this might deplete the bacteria in the bed and that toxicity and techniques for keeping holothurids should be discussed in such a recommendation , he dismissed those concerns as irrelevant out of hand, demanding I cite an expert. I did not bother, even though articles he had already cited by Borneman and Calfo included these caveats.
Gary and I have had many shared learning discussions over the years and I'd certainly listen to Gary's account of his experience long before I'd listen to someone else's interpretation of what Eric Borneman may have said.But I'd listen to Eric Borneman directly before I'd listen to Gary for most issues .
I can read a book or an article as can others as they choose.
I wan't to hear folk's experiences since anecdotal information has value to me and sharng experiences is a great way to learn. I think many get scared away for fear of ridicule, usually by someone who doesn't know very much but is all to willing to present personal opinion as fact.
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