Deep Sand Beds - Colin?

[chalcosoma]

Hello everybody, I suppose this question is mainly for Colin.... but open to anyone.

I was planning on having a Deep Sand Bed (and live rock) in my 500 L tank, which will house - fingers crossed - growing hatchling cuttlefish.

I've read your warning about these beds, but also read some accounts that claim they can work very well if done "properly".

They claim that the use of coarse coral sand, and not having the bed DEEP enough (only 3-4 inches), are what cause them to fail. Also that there must be plenty of tiny worms, rotifers, crustaceans, etc. but NO "sand-sifting" organisms like bristle stars that will eat these tiny beneficial organisms. Supposedly these organisms should be enough to keep much of the volume of the bed shifting and aerobic, with only a small portion anaerobic and no crusts. Additionally, sugar-fine oolitic sand...and it should be added to the tank only one inch at a time as it becomes live or something like that.

OK this is getting long but, given that I will have cuttles that will hide in the sand but not EXCAVATE like octos do, will this cause a problem?

I could just have deep sand in the sump, but IF it actually worked the way it's supposed to it should have a huge surface area for bacteria, much more than liverock.

Is my information outdated? Has anyone out there made a DSB work like it "ought to"? Or are DSB's a failed experiment?

Of course I will have a skimmer and do water changes as well on the tank.


Thanks,

Michael

 

[Thales]

I've read your warning about these beds, but also read some accounts that claim they can work very well if done "properly".

According to the major DSB advocates, this includes looking at sample of the sand under a microscope periodically to make sure you have the 'proper' amount of critters living in it, and if you don't, buying recharge kits to make sure you do.

They claim that the use of coarse coral sand, and not having the bed DEEP enough (only 3-4 inches), are what cause them to fail.

Coarse coral sand allows the detritus to settle and rot, but not break down - essentially it becomes a mechanical filter pad that is never cleaned.
As for the depth issue, the benefit I can see is that it will take longer for the bed to 'fill up' before it starts re releasing ickies back into the water.

Also that there must be plenty of tiny worms, rotifers, crustaceans, etc. but NO "sand-sifting" organisms like bristle stars that will eat these tiny beneficial organisms. Supposedly these organisms should be enough to keep much of the volume of the bed shifting and aerobic, with only a small portion anaerobic and no crusts. Additionally, sugar-fine oolitic sand...and it should be added to the tank only one inch at a time as it becomes live or something like that.

The issue I have with this is there doesn't seem to be any scientific evidence to back up these ideas. They sound good, but where are the papers? When asked, the DSB expert says the papers are out there, but refuses to cite which one.

OK this is getting long but, given that I will have cuttles that will hide in the sand but not EXCAVATE like octos do, will this cause a problem?

Shouldn't be a problem, but I guess the question is 'why do you want a DSB?'

I could just have deep sand in the sump, but IF it actually worked the way it's supposed to it should have a huge surface area for bacteria, much more than liverock.

There are some of the DSB experts that claim a remote DSB won't work. I also think any decent amount of LR will give you more than enough surface area for dentirification.

Is my information outdated? Has anyone out there made a DSB work like it "ought to"? Or are DSB's a failed experiment?

I ran a DSB for years in my reef - I just removed it because I was having issues with the re release of nutrients. I don't really see the utility of a DB in a tank where you want to have a no nutrient load - the bio load alone of the life in the sand is massive.
DSB's seem fine for soft coral tanks, or tanks that hold animals that need the sand, but for everything else I think they are not a good idea.

Of course I will have a skimmer and do water changes as well on the tank.

Then I would go with as little of a sand bed as possible and vacuum it once and a while - thats how I run my cuttle systems.



The DSB issue can get pretty deep pretty quick!

 

[Colin]

'The DSB issue can get pretty deep pretty quick!' said Righty

Luckily for me, Righty has already said a lot of what I would have said so it's not going to be too deep from me... LOL

Anyway, yes a lot has been said about the ole DSBs and the pros and cons... I dare you to have a look at some of the discussions on Reef Central! People actually got banned from the site after the 'debate' became so heated!

Lets cut to the chase... no more DSBull.

Cephalopods really don't live long enough to make worrying about installing a DSB worthwhile and by the time they have excreted their gallons of ammonia the DSB isn't going to be worth the sand its made of.

Now, I do think that the ethereal 'if it's set up right' DSB has a place for a reef tank where, and lets be honest, the whole idea is to pretty much have it nutrient free and with a light load of livestock. But its really not applicable to cephalopods. Unless you have the DSB in a 200 gal tank adjacent to the ceph tank?

Righty, did the DSB 'experts' not claim to have crashes after a few years too? Too many people claimed miracle work within a few months. Yes the nitrates went away to Nitrogen heaven but they cried wolf and later the time bomb went off.

I am an advocate of frequent water changes for dilution of nitrogenous wastes. If you want a huge bacterial culture build a huge wet/dry trickle filter and do regular water changes. I think it's much easier in the long haul.

Cheers
Colin

 

[Thales]

Righty, did the DSB 'experts' not claim to have crashes after a few years too? Too many people claimed miracle work within a few months. Yes the nitrates went away to Nitrogen heaven but they cried wolf and later the time bomb went off.

I know some people that have had successful SPS tanks with DSB's fo for over 10 years. I also know SPS people who have had crashes or sand 'events' losing 100's or 1000's in coral very quickly. I don't see why anyone would want such biomass in their tanks, especially if disturbing that biomass could kill off their tank! The way I think about DSB's is akin to sea apples - they aren't worth the risk.

RR

Oh - I also think the real problem with DSB's isn't the nitrogen issue, but the phosphate issue.

 

[chalcosoma]

Deep Sand Thoughts

Thanks Righty and Colin,

the ONE scientific study of DSB's I have read indicated very good removal of nitrates BUT higher than normal phosphates. I have since read that they are not recommended for Fish Only systems due to the fact that the critters/bacteria can't handle the nutrient overload. It it would really suck if something went horribly wrong with the whole thing and killed everything.

However as cephs are much more sentitive to NITRATES than fish, does this mean if I use a trickle filter that works well, won't I have a problem with it working "too well" and producing a nitrate spike?

In any case I'll opt for a shallow sand bed with live rock.

Thanks

 

[Thales]

Thanks Righty and Colin,
the ONE scientific study of DSB's I have read indicated very good removal of nitrates BUT higher than normal phosphates.

Do you have a link to that study? I cant find any scientific data on DSB's!.

I have since read that they are not recommended for Fish Only systems due to the fact that the critters/bacteria can't handle the nutrient overload.

Don't know about that - I would run one on a tank that was only going to be set up for a year or two, or a tank with animals that needed the sand.

It it would really suck if something went horribly wrong with the whole thing and killed everything.

It does!

However as cephs are much more sentitive to NITRATES than fish, does this mean if I use a trickle filter that works well, won't I have a problem with it working "too well" and producing a nitrate spike?

In any case I'll opt for a shallow sand bed with live rock.

Thanks

I wouldn't use a trickle filter either - your LR and skimmer should be plenty!

RR

 

[chalcosoma]

DSB Study Link

Righty,

here's the link:

http://www.reefs.org/library/talklog/p_auger_081599.html

Thanks again

 

[Scouse]

There was some very topical debates on Ultimate Reef aswell on DSB's should you want further reading, these may also point to any scientific study.

search for the name kim on there aswell...he spoke of them a lot.

cheers

 

[Colin]

I'll have to dissagree on the use of a trickle filter for a grow out tank for Sepia... If the tanks are set up for rearing cuttle juveniles then there is always going to be a lot of waste getting produced, in my opinion a wet/dry trickle filter would do a better job of keeping on top of the more toxic nitrogenous wastes than live rock would...

A skimmer is a must

Cheers all
Colin

 

[oscar]

well, despite all the debate - when i set up my tank i opted for a dsb not particularly knowing a lot about them but knowing that i wanted it to look pretty! It is about 6 or 7 inches deep down to about 3 in a few spots...

completely unreliable information so dont rely on this!!!: but i though maybe by having these shallow spots it would create dead spots in much of the sand bed so that while it would be physically deep for the most parts (the visible bits mainly) little of it would be active... hmmm...sounds stupider and stupider the more i consider it but hey it hasnt crashed yet (give it a week lol)

anyway despite my own disaster of a dsb screw-up (should have taken colin's advice...but then i wouldnt have a pretty sand bed!) if i could start from scratch i would go for:

4 inch sand bed with no anaerobic space - liverock - large skimmer or pair of skimmers - slightly smaller trickle filter to reduce immediate threats - refugium for cauerpa and other macro algae (keeping it groomed!) - to keep water good in the long term.

 

[Thales]

Righty,

here's the link:

http://www.reefs.org/library/talklog/p_auger_081599.html

Thanks again

Thanks! Best I've seen so far. This is what I found most interesting:

However, the nutrient data for the sand bed shows a slightly different value. In these graphs one can see the low nitrate, nitrite and hydrogen sulfide values. All of which are good news. However, the high phosphate values are worrisome. This data shows one particular anomaly, higher than normal levels of phosphate. One would typically expect to see some phosphate within the sediment area, but concentrations as high as those found within the bed are peculiar.

 

[Thales]

I'll have to dissagree on the use of a trickle filter for a grow out tank for Sepia... If the tanks are set up for rearing cuttle juveniles then there is always going to be a lot of waste getting produced, in my opinion a wet/dry trickle filter would do a better job of keeping on top of the more toxic nitrogenous wastes than live rock would...

A skimmer is a must

Cheers all
Colin

Fair enough Colin! From the reefing world, I am slightly conditioned to reject the idea of W/D - I'll have to re look at that.