Why don't intermediate depth sand beds work?

[Gary Majchrzak]

Gary, I truely hope your sand bed lasts forever as I never want to see anyone have problems and I have no doubt it is fine after 5 years. I feel that problems with those type of beds come about after ten years as there are not many DSB systems older than that. A few, but not many.

Paul- my remote DSB is fed clean water from my skimmer. No poop accumulates.

Now, if you're referring to a DSB in a display aquarium I agree- there's a limited amount of time before PO4 accumulates to a significant level. This is where MAINTENANCE becomes critical.... Not only with PO4 export but with critter counts / extinctions (Shimek)

 

[coralreefdoc]

Paul- my remote DSB is fed clean water from my skimmer. No poop accumulates.

This is why you're achieving successful results

Now, if you're referring to a DSB in a display aquarium I agree- there's a limited amount of time before PO4 accumulates to a significant level. This is where MAINTENANCE becomes critical.... Not only with PO4 export but with critter counts / extinctions (Shimek)

Exactly

 

[Paul B]

I don't see any tension.

I also don't see any tension, Hey Gary, do you see any tension?
We are just discussing. :dance:

 

[JPMagyar]

Here let me add back some tension :blown: , just kidding! No tension just a great discussion . . . even if it has been done before

If I am understanding correctly, the anti-DSB crowd believes that unmaintained DSBs are deadly phosphate sinks that will cause a tank to someday "crash" due to unleashing gobs of deadly phosphate into the tank.

Did I get that correct?

If that is not correct than ignore the following comments:

BUT

I disagree for two reasons:


1) Many SPS tanks exist with old DSBs that have not "crashed".


2) The premise is wrong as explained by the venerable R H-F:

Randy- In short, the sink will overflow. The heavier the load, the faster your sink will fill. The resulting flood is what causes your tank to crash.

Sounds scary, but when you think about it, how is a full to "overflowing" sand bed different from no sand bed at all? The bare bottom is also "overflowing" in that sense. It simply stops taking up phosphate. Unless you claim it to be a phosphate source, rather than just a full sink, I don't see the issue. I've never seen any evidence, but sure heard loads of opinions, that suggest sand beds become a source of P.

Please, please, please keep in mind I am expressing one guys opinion and am in no way disparaging anyone else's opinion. I know everyone here has awesome reefs of their own and are all here to add advice they feel is helpful. I'm just trying to provide an "opposing view" for any new reefers following along now or in the future. Having said that I hope such readers will keep in mind that I am NOT a scientist and am not offering THE answer, but simply expressing the opinion of a successful aquarist and the experiences I have had so far regarding Deep Sand Beds and their long term viability, AND if I am wrong then it could cost you a tank full of SPS plus I should note that I do NOT have a DSB but I surely do like to discuss stuff

Joe :beer:

 

[Paul B]

If I am understanding correctly, the anti-DSB crowd believes that unmaintained DSBs are deadly phosphate sinks that will cause a tank to someday "crash" due to unleashing gobs of deadly phosphate into the tank.

Did I get that correct?


1) Many SPS tanks exist with old DSBs that have not "crashed".


2) The premise is wrong as explained by the venerable R H-F:

I don't care about phosphate at all and never tested for it. I think DSBs will fail just because they will not process anything much longer than ten years.
And you don't have to keep apologizing, we all have different opinions and we are all right and wrong at the same time. Byt who really cares? It is a hobby and we are not sending space shuttles to fight off aliens, not yet anyway.

According to Shimek there are worms and I think he calls them critters that constantly tunnel through a DSB and there by keep it slightly porous so the water can get down to the lower areas and get processed. To me this will not work. The lower layers of a DSB are supposed to have no oxygen so those worms will not go there. Anerobic bacteria will stay there for a while but even they will die off from lack of food. It just can't work for long, but even if I am wrong about that, and I may be because I am not the God of DSBs, those worms will not reproduce forever. Most miniscule creatures have a very short lifespan, maybe just a few weeks and in the limited space of a tank, eventually inbreeding alone will lessen the population and they will stop reproducing. I would imagine you could somehow buy these things (I doubt it) but even if you could, there is that, no oxygen problem again and the lower layers will get no water flow.
If you take a 10 year old DSB and drill a hole in the bottom of the tank, water will not even leak out because the sand grains will be compacted. I have not tried this and I don't think anyone will volunteer so my theory is safe for now.

Even in the sea where I collect organisms I see this. If I remove the top inch or so of sand at low tide I will find hydrogen sulfide, it is very common because the sand here in NY is very fine. But if I dig much further the sand is again clean even though there is no oxygen there. It is clean because even the bacteria that produce hydrogen sulfide can't live in the lower layers due to lack of food.
This is the area I am talking about. The anerobic bacteria do not live from a few inches below the surface all the way to China. The sea has a DSB and even in the sea it doesn't work as Dr Shimek reports.
It's just my theory, I am sure there are some DSBs older than ten years but the vast majority crashed way before that.
Again, not the God of DSBs just an old, bald retired electrician.

 

[keithhays]

I don't see any tension.

In response to the past couple of posts, the ocean doesn't rely on deep sand beds to denitrify or maintain PO4 at low levels.
In fact, the varying salinity of oceanic currents liberate PO4 from substrate.

Incidentally, I try to get as much natural sunlight into my reef aquarium as possible.

Gary - I was being a bit silly with my answer, but I don't think the scientists agree with you. While deep water swells as I said do bring nutrients to surface, that is not the only thing happening. And while my definition of sand in my response was a little disingenuous, it was in quotes for a reason. Here is what is really happening and in pretty plain English:

http://www.princeton.edu/main/news/archive/S25/19/05M98/

Its a decent read if you are into this kind of thing.

 

[Gary Majchrzak]

Here let me add back some tension :blown: , just kidding! No tension just a great discussion . . . even if it has been done before

no kidding!

If I am understanding correctly, the anti-DSB crowd believes that unmaintained DSBs are deadly phosphate sinks that will cause a tank to someday "crash" due to unleashing gobs of deadly phosphate into the tank.

Did I get that correct?

Kinda. "Anti-DSB crowd" tends to divide people into two camps on this subject which is ridiculous (IMO). Like you already posted, it's a maintenance issue. Cut and dry. And the are different types of DSB's: remote and "in display". Personally, I like remote deep sandbeds (RDSB's) and I would recommend them due to their having very few maintenance issues. The same cannot be stated about "in tank" DSB's. Just ask Shimek, Goemans etc.

Originally Posted by Randy Holmes-Farley
In short, the sink will overflow. The heavier the load, the faster your sink will fill. The resulting flood is what causes your tank to crash.

Sounds scary, but when you think about it, how is a full to "overflowing" sand bed different from no sand bed at all? The bare bottom is also "overflowing" in that sense. It simply stops taking up phosphate. Unless you claim it to be a phosphate source, rather than just a full sink, I don't see the issue. I've never seen any evidence, but sure heard loads of opinions, that suggest sand beds become a source of P.

Here's the thing: critter poop can accumulate rather easily in/on a sandbed. (I've seen it form layers in some DSB's.) Not so on a barebottom with good water movement... (or if it does it's easily visible). Simple experiment one can perform (and we've done this in our reef club): collect some critter poop. Snails, fishes, cukes... you name it. Take two water samples from a given aquarium. Add the poop to one sample and not the other. Shake both samples up and take a PO4 reading.
PO4 inhibits calcification in scleractinians.
A sandbed quite simply allows a place for detritus to hide that's not available in a barebottom aquarium.
Can BB, SSB and DSB reef aquariums ALL be successful? You betcha! IT'S A MAINTENANCE ISSUE.

 

[Alavaster]

I couldn't agree more with EC.

 

[Gary Majchrzak]

Please, please, please keep in mind I am expressing one guys opinion and am in no way disparaging anyone else's opinion. I know everyone here has awesome reefs of their own and are all here to add advice they feel is helpful. I'm just trying to provide an "opposing view" for any new reefers following along now or in the future. Having said that I hope such readers will keep in mind that I am NOT a scientist and am not offering THE answer, but simply expressing the opinion of a successful aquarist and the experiences I have had so far regarding Deep Sand Beds and their long term viability, AND if I am wrong then it could cost you a tank full of SPS plus I should note that I do NOT have a DSB but I surely do like to discuss stuff

Joe :beer:

understood here

My own personal experience with 5 year old DSB: "old tank syndrome"
Stonies stopped growing and Xeniids flourished. All types of algae did very well. High PO4 levels that could not be corrected by 100% water changes.
Only until I removed my detritus laden critter count depleted in display DSB did things dramatically turn around. It's something we should all experience.
Many have. Many more have not.

 

[Gary Majchrzak]

Gary - I was being a bit silly with my answer, but I don't think the scientists agree with you. While deep water swells as I said do bring nutrients to surface, that is not the only thing happening. And while my definition of sand in my response was a little disingenuous, it was in quotes for a reason. Here is what is really happening and in pretty plain English:

http://www.princeton.edu/main/news/archive/S25/19/05M98/

Its a decent read if you are into this kind of thing.

Yes DSB's denitrify. That's why I run one remote. I'll stand by my previous post:

the ocean doesn't rely on deep sand beds to denitrify or maintain PO4 at low levels.
In fact, the varying salinity of oceanic currents liberate PO4 from substrate.

 

[Paul B]

A sandbed quite simply allows a place for detritus to hide that's not available in a barebottom aquarium.
Can BB, SSB and DSB reef aquariums ALL be successful? You betcha! IT'S A MAINTENANCE ISSUE.

Dam, I am always left out with my Reverse UG filter. I think I will go eat worms.

 

[Nanook]

Dam, I am always left out with my Reverse UG filter. I think I will go eat worms.

We can't all be special

 

[JPMagyar]

Gary & Paul,

Great stuff guys!

I don't know if I'm a DSB fan or not after reading through your thoughts, but I sure have a LOT more to think about.

Thanks!


Joe :beer:



P.S. What the heck is a Reverse Under Gravel Filter? That sounds like something from a Flintstones episode

 

[Paul B]

I don't know if I'm a DSB fan or not after reading through your thoughts, but I sure have a LOT more to think about.

Thanks!

If you are unsure as to what substrait to use, consider replacing your water with saw dust, then it would not matter as much what you have on the bottom of your tank. :wavehand:

 

[Meanmike]

Could this be resolved by removing a small portion of the DSB slowly over the coarse of several months? And then replace some of the sand with live sand directly from the ocean not the packaged stuff? Maybe do this every three or four years.

 

[Gary Majchrzak]

Could this be resolved by removing a small portion of the DSB slowly over the coarse of several months? And then replace some of the sand with live sand directly from the ocean not the packaged stuff? Maybe do this every three or four years.

knock your socks off. Removing and replacing sand (to remove detritus trapped in the sand) wasn't my cup of tea so I quit doing it years ago. Ditto with replacing extinct sandbed infauna. (PS: there are places that sell "recharge kits").

Why not simply remove an in-tank DSB and NOT replace it?

Paul- I apologize for leaving out the UGF :facepalm:

Hey- this is the kind of informative thread we used to have years ago. Thanks for your participation!

 

[keithhays]

knock your socks off. Removing and replacing sand (to remove detritus trapped in the sand) wasn't my cup of tea so I quit doing it years ago. Ditto with replacing extinct sandbed infauna. (PS: there are places that sell "recharge kits").

Why not simply remove an in-tank DSB and NOT replace it?

Paul- I apologize for leaving out the UGF :facepalm:

Hey- this is the kind of informative thread we used to have years ago. Thanks for your participation!

I wish everyone had your attitude.

 

[Paul B]

Paul- I apologize for leaving out the UGF

Gary, no need, I am fairly sure I am the only one with one.

 

[keithhays]

Gary, no need, I am fairly sure I am the only one with one.

I doubt that, there are a lot of people who started with a garf setup, they just don't call it a UGF.

 

[MHG]

I agree somewhat with EC. My corals have never looked better since I started to vacuum my sand bed every week.

Comparing a closed system to mother nature is absurd. Mother natures sand bed is bottomless (almost) and the top few feet gets tossed regularly by storms... Kind of like cleaning.


I agree with the principal. Vacuum or dont. Pick one and stick to it. However if you choose not too you will eventually have a problem...