Proper depth of LS

[susan]

I'm starting up my tank this weekend!
Here's my q:
I want a 4in DLSB in my 55gal reef tank. From what I hear on this forum, that's great! My delema however, rests with the LFS people.
They say my bed should be only 1/2 to 1in thick because the bacteria/critters only live in the top 1/2 inch and so deeper down everything dies and the bed gets all nasty.
If that's true, why go with a DSB? (I'll be starting with 150lbs Southdown and 20lbs LS placed over that, with 60-80 lbs LR to top it all off.)
So what's the deal? Thanks!

 

[25gator]

a deap sand bed is fine with a correct plenum. thats 3/4 tubing with eggcrate over that then a 2" layer of crushed coral then screaning then 2" of sand that is supposed to get rid of nitrates (BUT) if not done right it poisons the tank with sulfer dioxide i think could be another cemical your lfs is right in a way! many ways to do the same thing. i have aprox. 1" of ls in my 180 less work and risk!!!!!!!!

 

[aj77]

You need only search all the past threads on DSB and LS etc, to get a few days' worth of reading on this subject.
The majority view seems to hold that a DSB/LR setup is most effective, but this has been expounded by many others with much more experience than me.
AJ

 

[blackdog]

Hopefully people with more experience will chime in on this, but here's my understanding. The preferred system (around here at least) is a 4-6" sand bed, which is also called the Berlin system. The reason the bed needs to be that deep is so there is an area of anaerobic bacterial activity. I've seen debates over whether the anaerobic bacteria produce toxic gases, but there are lots of people using a DSB successfully for a long time, and in general it seems easier than creating a plenum (Jaubert method).
I recently started a 55 gallon tank, and used 90 lbs of Southdown and 20 lbs live sand. I should have used all 100 lbs of Southdown. However, 150 lbs is too much -- 120 lbs of sand will give you between 4-5" sand bed in a 55 gallon 48" long tank.
Rinse the Southdown several times in a Rubbermaid tub before putting it in the tank. Every time I touch my sand bed a huge amount of silt gets stirred up.
What LFS are you going to? I heard there was a place in Portsmouth that might be good.

 

[fshhub]

actually a dsb is outstanding, wihtout the plenum, 4 ot 6 inches, and the as pockets you are referring to , are not a problem, if done right, in fact, fi you do not stack the rock, on the sand, there is NO chance of it,but even if you do, then otherws will testify that it still is not a problem
and to answer you susan, your lfs like many others nation wide(are untrusted in this hobby by enthusiasts), preach against the use of a dsb and like either ugfs or wet drys, but let me put it this way,
ever bought a used car??? sales men have all the good answers don't they, especially if they have a product to sell
do not get me wrong, i am a very good sales man and do not knock the trade, but IMO most of us cna sell you on anything if we are good, and if it goes agianst eh products i am trying to sell i can do an outstanding job of it
now about hte bacteria, the bacteria you want for nitrate reduction is anaerobic, which means it lives in the absense of oxygen, so how deep of a be do you need to achieve oxygen free zones, the answeris more than 2, and 3 is marginal, but 4 or more is best, but anything over 6 is no extra benefit
and if it is a new tank, i advise against rinsing the sand, it will settle by the time the cycle is over, especiallly if you top it with ls too, it is fine, bu t it will settle and stir less
HTH and good luck

 

[msb27]

I read this book on plenum systems written by Bob Goemans, Ph.D., he states that sandbed effiency is directly related to its depth of dissolved oxygen. Without the plenum the sandbeds dissolved oxygen penetrates about an inch or less, and substrate below this becomes anaerobic resulting in the loss of balanced microbial process. This favors nutrient storage which will lead to algae problems. I set my 55 gal up on friday with a plenum, they are very easy to make yourself for only about $20. The plenum is supposed to extend the efficient anoxic microbial processing area throughout the entire sandbed. He says that this will provide for a far greater bio-load capacity.
Anyways, thats what this guy says. A buddy of mine has 55 with plenum and a 4 inch sandbed. He says that he has it loaded to the gills with fish and corals and stuff, it has been this way for about a year and a half and everything seem to be in check. Is this because of a plenum, I dont know. But it convinced me to spen 30 mins. and $20 to build one for mine!!
Scott

 

[fshhub]

plenums, IMO are good, but no better than a dsb and more work(not much,), especially if you do have to do anything down the road for maintenance or changing or moving, that is all, not that they are bad, just more than needed

 

[25gator]

msb27 you are right! i saw that book also. i suck at typing so i cant go into it. but i believe the rock will do the same job. i hope were both right in ten years! for the fishis sake! but i would never put 4-6 in of sand without the plenum! toooo risky! this will be a problem in the year to come.i think! <img src="graemlins//confused.gif" border="0" alt="[confused]" />

 

[fshhub]

something is fishy here,
first you start off with advise that you know most of us here will advise against, then you put up a big flag asking us all to come here, then....
why??
for a big debate, in your 10 years of experience(which is semi outdated, hence the toxic pocket theory), you want to jump in and state that the lfs's you visit are the best thing since sliced bread and the dsb is no good(another much outdated theory), well i visit many lfs's like that too, and they refuse to change their opinions(na dboy did me and others here prove them wrong), and several of us here have offered much support to the fact that a plenum is not necessary, and this is all based upon nearly as much experience(and combined much more),
without the use of a book that has been out for over 5 years(that i know of, copyright i have is 1997, so may even be older), not knowcking bob goeman, like i said, plenums are good too,but much has changed in this hobby in 5 plus years, we all have to admit that(ugf's were aound much longer, but........)

 

[msb27]

I wasnt saying which way was right or wrong. Just going on what ive read and seen myself. The book I refered to(copyrighted 2000) is not the only resource ive read on the subject of plenums. Everybody (or alot of people)says not to use crushed coral, but alot of people do with some success. People are going to use what they think deep down is right to use, not just because what you or I think. Shoot I was told by numerous people that I had to use damsels to cycle my tank, or raw seafood, but I didnt use either one. Does that make me right and those people wrong? No way!! Everybody is gonna set up a little different. Ive always heard 4 to 6 inch sandbed, probably 50 percent of the tanks Ive seen had 4 inches, even the well established reefs at my LFS dont have 4 inches of sand and everything seems to be thriving.
Scott

 

[fshhub]

msb, i agree that plenums are not bad, i said it several times, and bob goemans wrote a couple of books, was that live sand secrets??, probably re released in 2000(again), if so
i was jsut pointing out that we were invited to come in and then get the argument that dsb's are deadly(argument, being repost stating it over again and his experience, saying he must be right, hence we must be wrong in the way it was worded)
and
oh yeah, i forgot to add earlier that the plenum is based on the fact of reduced oxygen zones, not oxygen free zones, which is what the bacteria needs to flourish properly(no oxygen is the desired effect),
i prefer to follow the oldest documented and proven method we have:
how mother nature did it, without a screen 2 inches under the floor of the ocean, if the dsb is soooooooooo bad, how could she have succeeded for so long

 

[nm reef]

Attached below is a link to a good article on DSB's.....I could attach several others that also support the idea of a 4"-6" dsb of assorted grain sizes that support a diversity of fauna...bottom line from what I've seen and heard is that a pleueum will work...but so will a diverse DSB...then I ask myself.....do I want a sand bed or a plactic structure that supports a not so DSB...after reading all I could find I went with a DSB!!Debate could go on forever.....but its the same as any other issue....do the requiried research and make an informed/educated choice. Personally I've decided that a DSB is the way to go.......lots of people have success with other systems....kewl....mine works for me!
<a href="http://www.rshimek.com/reef/sediment.htm" target="_blank">DSB</a>

 

[broomer5]

I'm sure we all could LEARN to run a saltwater tank sucessfully with a bare glass bottom, plenum, DSB, shallow sandbed, crushed coral or aragonite shell hash.
They all work.
They all have their own advantages.
They all have their own disadvantages.
Ease of maintenance, long term stability, the marine creatures you plan to keep and knowing what you want to acomplish is the key.
In my opinion and many others, there's no one right way to do it-no matter what you may hear or read.

 

[kelly]

I have to agree with Broomer5. I currently have 3 tanks. My main tank an 80 gallon tank has an under gravel filter, and about 1" of crushed coral. It has been running for over 10 years this way. No nitrates, nitrites, ammonia, etc.. I do not advocate this, but it worked for me. I do not siphon the crushed coral, just do regular water changes, clean the glass, etc..
The 2nd tank is a nano-reef with a 2" sand bed, and the 3rd has a 4" DSB. These 2 tanks have not been up long enough to make any decisions. I personally would go with a 4" DSB. I am not going to change my main tank in the near future, but from what I have read and pondered over, the DSB is the way to go. Just my 2 cents worth.

 

[marine qa]

Just one quick point: No one on this board has experienced a toxic gas emission from a DSB, nor has anyone on this board ever relayed first hand knowledge of one ever occuring.
More quick points: I personally have had a 5+ inc dsb in my tank, and roughly a 4inc in my sump for over a year. My water quality has always been perfect and I do absolutely no maintenance to the dsb. These beds are naturally inhabited by bristle worms and are picked over by scarlet crabs.
One quick suggestion:
Susan, in my opinion, I would countinue to double check info from your LFS before implementing it.

 

[25gator]

i was'nt trying to start a battle just a discution. susan posted and knowone was answering. we all have a reef with different setups, none are wrong! just our way. thank you, but it looks we're taking it the (dolphin) road. but as far as mother nature goes there is way to much that i dont know about that(discovery can't even go there) <img src="graemlins//urrr.gif" border="0" alt="[urrr]" /> but we all have are own way i feel it could get risky with a dsb in 5-10yrs. thanks again for your input.

 

[kelly]

25gator,
Some of us enjoy these types of discussions, that is how we learn. Although others may disagree that is fine. I know that most people would not have my setup, and it really does not matter. As our knowledge of the hobby increases so do the ways that we keep our tanks. Years ago, almost no one keep nano reef tanks, now they are quite popular.
Until recently I never heard of miracle mud, now some think it is the way of the future. I can remember when wet/dry systems were seen as the best thing going. I personally do not like them.
Some recommend skimmers, some don't. There are things that are popular, and things that are not. It is nice to have a forum that we can share our experiences, opinions, successes and failures with others. Hopefully we can learn for each others mistakes and successes and have a successful reef tank dispite ourselves.

 

[susan]

WHOA! That was intense!!
Thanks for your uh, input guys and gals.
Considering, I'm very DIY handycapped, I think I'll go with the 4-5in DSB. I wanted that anyway. I just wanted to know the difference between shallow vs deep BEFORE putting it in. I know now know in no uncertain terms!
Thank you.
PS. SMILE A LITTLE PEOPLE- It'll do you AND OTHERES good!

 

[blackdog]

Just to salt the stew a little, I thought I'd add one other reason I wanted to go with a DSB.
I'd really like to add a jawfish to my tank at some point. I've read about them and seen one in action briefly and they seem very entertaining. I won't go into the downsides of a jawfish, bc we don't need another debate, but a jawfish needs at least 4-5" of sand to make his tunnels. Ergo, no plenum for me.
OK, one other reason I can think of. The more sand (as long as it is Calcium-based, like Southdown or CaribSea) the better, because it help keep the alkalinity and pH up.

 

[twoods71]

Also a 6 inch sand bed of course grain sand can have the same effect as a 2 inch sand bed with a very fine grain sand.