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Anonymous

Guest
I have decided to set up a deep sand bed after reading some of Biogeek's posts and many others over the use of a plenum type design. I wanted to get some guidiance on how to place the live rock. I realize that the more surface expose of the live sand bed the better. Should I support with adequete pieces of cut PVC on end so that the live rock is hovering 0-1" above the sand bed? Or should I place the live rocck directly on top of the sand bed? Or place the live rock on the glass bottom and fill the sand around?
Thanks for any help.
 
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Anonymous

Guest
What I did was cut 1 1/2 inch PVC 4 inches long and glued eggcrate to it. I then placed this unit on the bottom of the tank, added 4 inches of aragamax sand to just cover the unit, then placed my LR on top of the eggcrate. This way, the rock isn't compacting the sand and full benefit is received. HTH, Ted
 
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Anonymous

Guest
Hi DGB,

You definitely will not want to put the live rock directly on the sand bed. Any compaction of the sand defeats its purpose. Either use PVC or a new product called reef timber. I am not sure who the manufacturer is, but the product keeps the rock off the sand bed very well.

Good luck!
 
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Anonymous

Guest
I used a similar approach as Ted. I positioned a piece of eggcrate about 1 inch below the top of the sand bed. The eggcrate does several things: 1) it limits the depth that the rock will penetrate the sand bed; 2) it keeps the rock from sliding around (as opposed to a slick glass bottom); and 3) it keeps sand butrrowing fish out of the deeper layers of the sand bed.

I was not concerned about compaction. Unless the rock is on top of large areas of sand, the compaction should be minimal. I would, however, be concerned about inhibiting circulation around the rock and the sand bed. To solve this, I tried to use rock having irregular shapes and positioned so that the area the rock contacts the bed is minimized.
 
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Anonymous

Guest
Keep the LR up. It helps keep the sand detritus free and prevents compation of the sand. I use the PVC rack method, and I can hrdly see the PVC anymore because of the coralline algae growing all over it. Not so ugly anymore.
 
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Anonymous

Guest
To be a voice of dissent. Putting the rock in the sand is perfectly ok, probably even good. If you go with a sand bed chances are it will be about 4" deep. I have my rock about 1" deep in the sand. You will, as you know from reading Biogeek's posts, need to add some live sand and/or detritivore kits. I suggest both from several sources. These critters eat detritus, Therefore the detritus is beneficial to have on the bottom of the tank. Sand compaction isn't a problem. Ever walk on a wet sand beach? Unless you try very hard you won't leave a footprint. Due to the size of the grains(most should be 0.5mm or so) we use it to backfill ditches in construction many times because it is already compacted when it gets dumped in. There may be a small amount of displacement when placing the rock. I am not sure what srbayless means when he says compaction defeats the purpose of a sand bed. The purpose of mine is denitrification which takes place in anoxic(oxygen-less) areas of the bed. The rock on/in the sand possibly aids in this by keeping circulation, and therefore oxygen, down. Another purpose is to feed my corals and clams. The critters that live in the sand reproduce creating larvae which feed the other critters in my tank. Hope this helps.
 
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Anonymous

Guest
I agree. Live Rock can certainly touch a deep sand bed, limiting the area it touches is what is important. In my reef with a plenum I used small peices of tufa rock (calcium based rock) and glued them to the undersides of the big peices of live rock so that it only touches the sand bed in a few small places (as if on small pedastals), this also makes small caves for fish to use. It works great and accomplishes the leaving of at least 75% of the sandbed area open. The tufa rock has over about a year become encrusted with corallines etc. and looks more natural than a PVC or eggcrate shelf. However my tank is fairly small so the rock doesn't sink to deep into the sand, with large mounds of LR the under sand Eggcrate support is a better idea along with minimizing rock contact. Just thought I'd throw what worked for me out there.

------------------
Neptune
 
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Anonymous

Guest
I agree with fishncoral,
According to Biogeek, having pvc or eggcrate or any thing else in the bed to help raise the live rock actually does more harm than good. It doesn't allow the detritovores to stir the bed and consume all of the detritus. I have my rock sitting directly on my bed and have had no problems whatsoever.
Now, if you go with a plenum, then according to Jaubert, you want to have as little contact with the bed as possible. This is to maximum water contact. But, I see it as being kind of pointless to do that because one of the main componets to the plenum is live sand.

Just my $.02
Ocean
 
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Anonymous

Guest
I really dont see a reason to suspend the rockwork above a properly setup and populated deep sand bed. Proper infauna will consume any detritus and prevent any compacting.

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Dan
Minotaur15 on #reefs
Captive propagation will be our salvation. Do your part.
 
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Anonymous

Guest
Use the KISS method (Keep it Simple). Remember, reefkeeping is not about power tools and equipment, it's about the animals in your care.

Therefore, I would suggest just putting the rock on top of your deep sand bed. You can wiggle the rock in a ways too if you want, for stability.

In 10 yrs of reefkeeping, I have never had my rock "collapse"

HTH
James Wiseman

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Reefs.org Channel Operator
 
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Anonymous

Guest
I have most of my rock on eggcrate raised 1" off the sandbed via PVC pipes. That way cukes can get at it. Can't see the egcrate by placing a few rocks on the sand at the front. I woulda thought this was the ideal way to go. Using almost 100% of the sand bed.
Brad
 
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Anonymous

Guest
I would sugest getting some clear acrylic rod and drilling rockbase bottem and using rod to suspend base a little above sand.
although i have a bare bottem i wish i would have done this when i setup mine.

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surfinbill
 
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Anonymous

Guest
I'm with somebody up there, denitrification bacteria are anerobic, no O2, compaction is no big deal. where does the rock sit on the ocean floor, in the sand, is there pvc and eggcrate below it...no...is there a plenum below it...no (of course there isn't glass below it either)..but I still say all natural!!!

Clark
 

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