Rock and Sand Question

ty_05_f

Active Member
A LFS that I don't normally go to told me i should lift all my rock of the sand bed. He said to do this b/c the anarobic bacteria would grow underneath the rock and cause bad problems. So should i lift every thing and but some pvc under my rock???
 

yetex

Member
I wouldn't think so. Look at how many people on here have the rocks on the sand bed with out a problem. I have yet to have any problem with it in my tank.
 

cboyfan2020

Active Member
how deep is your sandbed? If you have a DSB that is what you want. you want that bacteria to breakdown the nitrates.:confused: My rock is sitting on eggcrate with sand filling in all the square. this is too help prevent avalanches but if your Sandbed is only 2-3" deep anaerobic bacteria wouldnt grow there anyways. they need a lack of oxygen hence the anaerobic name
 

ty_05_f

Active Member
Yeah the anarobic would grow underneath the rock where there would be a lack of oxygen. I have a DSB it is 4-5 inches deep. I was just going to but some pvc cut in half on top of the sand and put the rock on top. Then hide the pvc with some sand around it
 
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irenicus

Guest
I know some people have all their rock sealed together. I wouldn't think it would be possible to lift the rock to vacuum under. I wouldn't worry. But I could be in the wrong.
 

timo

Member
From what I understand, one does not want to vacuum a DSB. Also, isn't anaerobic activity the good part of a DSB?
:p
 
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thomas712

Guest

Originally posted by cboyfan2020
but if your Sandbed is only 2-3" deep anaerobic bacteria wouldnt grow there anyways. they need a lack of oxygen hence the anaerobic name

Don't bet on that. If your sand is fine enough it can and will happen.
Thomas
 

cboyfan2020

Active Member
Thomas, my sand bed is only 2" deep and it is Caribsea. would this yeild an anaerobic enviroment? It is only deep enough to cover the eggcrate under my rocks but deeper in front and to the side of the rocks.
 
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thomas712

Guest
I have the eggcrate like you 1/4 inch on the bottom and in some places up to 2 inches of sand.
Now Dr. Ron says that the oxygen deprived areas normally will not happen in anything less than a 6 inch sand bed, I could agree in part with him on this.
In my opinion it can happen underneath the rocks of a 2 or 3 inch sandbed. Factors here would include your rock, the size of your sand, of course the finer the better until you reach mud (which I do not prefer). If you do not have enough water ciruculation. If you were to use the Grunge which is rock rubble and any other thing that could prevent the water ciruculation to your sand bed, if your pods, worms and such are depleted and not turning your sandbed over. If our (yours and mine) rocks are sitting on top of the eggcrate what about those areas that the rock has trapped the sand in those little squares? Will the water flow through it?
I Just feel that we can not say that it is not possable to have an anoxic area where the oxyegen is depleated and hydrogen sulfide could not develop even in a shallow sandbed.
Overall I would say that we are safe. But I worry about the long term possablility in the area underneath my rock.
Perhaps with my own personal sandbed issues I over worry about it. Guess it comes down to preference. But who am I. Certanly not a DR. with years of experience and research, not to mention testing, behind me. Just my opinion.
Thomas
 
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