DSB, SSB or BB?

[clintcar]

Hi Esteemed SG Reefers!

There has been much discussion about DSB vs SSB and BB on other forums.

While DSB's (4" and more) provide efficient NNR, its long term viability over 4 - 7 years has been brought into question. The progressive depletion of infauna and sand-stirrers in what becomes essentially a nutrient sink, leading to hydrogen sulfide and phosphate buildup, apparently may cause a possible deep-sandbed crash after a number of years.

There is some argument that SSB's (1" or less) or going BB is safer in the long term as they do not become nutrient sinks since detritus can be easily removed by siphoning or remains suspended in the water column for removal by the sump filters. I noticed one accomplished reefer on this forum going to the extent of removing his established DSB, leaving only about 1/2" of sand for aesthetics. Such a drastic measure must indeed be motivated by indications of impending danger!

Currently my sandbed is 2 - 2 1/2" inches thick -- I was afraid to commit to a DSB when I set up this, my first tank. Unfortunately, according to Calfo and other gurus anything less than 3" but more than 1" is a 'no-man's land', neither enough for NNR or for the sandbed to maintain a totally aerobic state. But I must say that this depth has worked fine for me so far, after more than a year. But then again I've yet to look under some of my larger pieces of rock..

Personally I find the BB look unnatural and a 1/2" sandbed probably chafes uncomfortably for sandbed dwelling corals, not to mention being inhospitable for sand-burying wrasses seeking sleep or refuge.

Which do you use in your setup? It would be interesting to see the differing opinions and observations of the more experienced reefers here.

[loonz]

My sandbed's about 3"...for about 8 years...no problems.

[Blenny]

If possible have a remote deep sand bed that you can disconnect IF it ever fail. In the tank I would prefer 1 - 2 inch of sand more for looking natural. Currently running 3 sand beds (2 with plenum and 1 with grade 0 sand) So far so good. No problems with nitrates and phosphates (using Salifert Test kits).. Maybe sand bed of the 2.5 ft ulva fudge that is helping to keep these parameters in check

[giantbicycle]

If possible have a remote deep sand bed that you can disconnect IF it ever fail.

care to explain further what this means?

[brittlestars]

Hi clintcar, just add another idea to SSB method.

Would it be wise to place an egg-crate first before putting sand to SSB level (abt 1")? Egg-crate is to provide a more stable footprint for LR.

[Blenny]

care to explain further what this means?

What I am trying to say is if you can have another tank / fiberglass to act as an additional sump and if the sand bed were to fail then by pass the circulation and clear out the affected tank / fiberglass sump if needed.

[clintcar]

Loonz: <<My sandbed's about 3"...for about 8 years...no problems. >>

Loonz, great to hear that! Care to share any maintenance tricks? Do you siphon detritus off the sandbed? Having had your sandbed in place for so long, how often have you had to replenish sand?

Brittlestars: <<Would it be wise to place an egg-crate first before putting sand to SSB level (abt 1")? Egg-crate is to provide a more stable footprint for LR.>>

Yes, other than adding stability, I have read that this technique is also used to elevate LR off the sand to prevent formation of black hydrogen sulfide patches from forming under the rock. Or help minimize their occurrence at any rate. No personal experience with this idea though. Have you tried this for yourself? One drawback is that in a SSB setup, the crate might become visible in some areas as sand forms dunes with powerhead currents and fish activity. I wonder also how wrasses that bury themselves in sand to sleep would fare in such conditions, indeed even in an eggcrate-less SSB setup.

Blenny: <<If possible have a remote deep sand bed that you can disconnect IF it ever fail. >>

A good idea, these remote deep sandbed and refugium combos -- if large enough they provide efficient NNR and a continuous feast of 'pods for the fish! This probably comes closest to replicating nature. Do you run such a system on your setup?

Thanks all, for your replies. Your input is much valued. I'm setting up a new tank this week and I'll probably go with the SB depth of my present tank, 2 - 2 1/2". Unless someone with a bad prior experience with this sand depth warns me otherwise!..

[Blenny]

Yes I am running with 1 sump and 1 fuge

[brittlestars]

Brittlestars: <<Would it be wise to place an egg-crate first before putting sand to SSB level (abt 1")? Egg-crate is to provide a more stable footprint for LR.>>

Yes, other than adding stability, I have read that this technique is also used to elevate LR off the sand to prevent formation of black hydrogen sulfide patches from forming under the rock. Or help minimize their occurrence at any rate. No personal experience with this idea though. Have you tried this for yourself? One drawback is that in a SSB setup, the crate might become visible in some areas as sand forms dunes with powerhead currents and fish activity. I wonder also how wrasses that bury themselves in sand to sleep would fare in such conditions, indeed even in an eggcrate-less SSB setup.

Nope, I have not tried it myself yet.

If you are keeping wrasses, one way is cut the egg-crate so that it only serves as footprint for LR, ie. DO NOT fill entire tank bottom with egg-crate. Hopefully, wrasses bury in areas where there is no egg-crate?

[May&Bruce]

Am running a plenum system in a 5 foot tank. This has a 5-6" sand bed on top of the plenum, with the sand grain size exactly as recommended by Julian Sprung. So far, it has only been a year and no problems whatsoever. I have one san-dsifting goby and 3 sand dollars. These keep the sand clean and i have never had to vacuum any detritus away.

So far I am very happy with the system......but it is only one year into it.....

[kenkht]

Since we are talkin about DSB, what type of substrate to use and what size. Can I use coral sand and say grade 0??

[clintcar]

Since we are talkin about DSB, what type of substrate to use and what size. Can I use coral sand and say grade 0??

For a DSB sugar-fine sand throughout is generally recommended, to a depth of no less that 4" with 6" being preferable.

It is also not recommended to mix coral sand with fine sand in a DSB as it would cause the fine grain sand to progressively be displaced, over many months, to the bottom layer of the sandbed with the coarser sand forming most of the upper layer. Mixing radically different sand grades would also inhibit the work and benefits that sand-stirring infauna provide.

Basically you want relatively uniform fine sand in a DSB.

[clintcar]

Am running a plenum system in a 5 foot tank. This has a 5-6" sand bed on top of the plenum, with the sand grain size exactly as recommended by Julian Sprung. So far, it has only been a year and no problems whatsoever.

Thanks for that. I don't know of many reefers in SG who run a plenum but it is an interesting methodology nonetheless. I wonder exactly how long the plenum in the Monaco aquarium has been in place, since Jaubert did implement it there first.

Did you start with a plenum or were you a former DSB advocate that went with a plenum later on with a new setup?

[loster]

i am running BB. it gives me better control of nutrients now, i have 90% of coraline algae covered on the base of my tank

[May&Bruce]

Thanks for that. I don't know of many reefers in SG who run a plenum but it is an interesting methodology nonetheless. I wonder exactly how long the plenum in the Monaco aquarium has been in place, since Jaubert did implement it there first.

Did you start with a plenum or were you a former DSB advocate that went with a plenum later on with a new setup?

I started with a 3 foot tank with DSB and after a year upgraded to a 5 foot 150 gal LPS reef tank. Jaubert's Monaco tanks have been going 5-10 years or so. I know a guy in SG with a small plenum tank keeping LPS and he claims that he has never done a water change!

Anyway, as I siad mine is only coming on a year old, so I am not in a position to really judge, although so far I am quite happy.