Glimmerman911
New member
Go through the wall for the 29g, much more room to play with that 10g. And there is no problem with the overflow going into the bucket then sump, as long as the flow is slow enough.
<a href=showthread.php?s=&postid=6468210#post6468210 target=_blank>Originally posted</a> by kevin2000
DSB's have aerobic, anoxic and anaerobic regions in their sand bed -- with the anoxic region sitting between the aerobic and anaerobic regions. The anoxic region has some/more oxygen than the anaerobic region. Basically its the difference between severe depeletion and having zip oxygen.
While that is a common belief I have never read anything that supports that position .. including Dr. Rons DSB article. You can have a sand bed a mile deep but that does not necessarily mean your going to appreciably more de-nitrification than my 6 inch DSB.<a href=showthread.php?s=&postid=6474555#post6474555 target=_blank>Originally posted</a> by grochmal
It sounds to me like the deeper the sand bed is, the larger this anoxic layer is which would mean more anaerobic bacteria, no?
<a href=showthread.php?s=&postid=6479549#post6479549 target=_blank>Originally posted</a> by kevin2000
While that is a common belief I have never read anything that supports that position .. including Dr. Rons DSB article. You can have a sand bed a mile deep but that does not necessarily mean your going to appreciably more de-nitrification than my 6 inch DSB.
<a href=showthread.php?s=&postid=6481653#post6481653 target=_blank>Originally posted</a> by mmmmsushi
While I don't have any science to back it up I would think that this position is correct. The water actually has to flow down to the anoxic layers and then mix with the free flowing water. I would think that this mixing only happens in a certain depth of substrate. Eventually you get to a depth where the water has already become depleted of the nitrates that we are hoping to remove.
That being said, it would probably depend on things like grain size water movement and maybe surface area. Or not. So I couldn't begin to comment on whether it's 6" or 36".
Matrixâ„¢ is a highly porous media designed to provide exceptionally efficient biofiltration for single site removal of ammonia, nitrite, and nitrate from freshwater, marine, and reef aquaria. Each liter of Matrixâ„¢ provides over 160,000 cm2 (170 sq. ft.) of surface, equivalent to over 40 L (10 gallons) of typical plastic ball media! This product is sold by volume. Cited weight is minimal weight.
Aerobic bacteria grow on the pitted external surfaces of Matrixâ„¢ and convert ammonia to nitrite and nitrite to nitrate.
These pores which cover Matrixâ„¢ are home to anaerobic bacteria.
Anaerobic bacteria convert nitrate into nitrogen gas, which is then expelled at the tank surface
<a href=showthread.php?s=&postid=6487831#post6487831 target=_blank>Originally posted</a> by captbunzo
You have to remember that when speaking in the terms aerobic, anoxic, and anaerobic, water is relatively LOADED with oxygen. Consequently, any sand bed which has water flowing through it will end up being aerobic, which defeats the entire point of what we are trying to accomplish here. I think the confusion comes in understanding HOW nitrates (and other molecules) come to exist in the anoxic and anaerobic layers of a sand bed. The answer is found in the wonder of diffusion. To quote google....
"The movement of suspended or dissolved particles from a more concentrated to a less concentrated area. The process tends to distribute the particles more uniformly." (source)
I know a lot of people won't understand this or just not believe it, but wow...these are great posts, this is third year undergraduate physics. The forces at work here are so strong and on such a small scale that sand particles, which are relatively big, won't stop or hurt this diffusion process.<a href=showthread.php?s=&postid=6488367#post6488367 target=_blank>Originally posted</a> by Spuds725
On the molecular level, the nitrate won't have any problem getting past the sand particles--- it won't have to flow, only diffuse (dilute) and this occurs via the 2nd law of thermodynamics--- that is the motive force, not water flow....
<a href=showthread.php?s=&postid=6490599#post6490599 target=_blank>Originally posted</a> by kimoyo
I know a lot of people won't understand this or just not believe it, but wow...these are great posts, this is third year undergraduate physics. The forces at work here are so strong and on such a small scale that sand particles, which are relatively big, won't stop or hurt this diffusion process.
When people say that you need infauna/bioturbation (their primary function) to get nutrients to the lower levels of a sand bed I just don't understand why.
Just looking at the result of this thread should be enough proof.
<a href=showthread.php?s=&postid=6489938#post6489938 target=_blank>Originally posted</a> by grochmal
Anthony, good to see you're still around (even in a limited fashion).
Can you or someone else help clear up something for me?
Everyone keeps describing the sand band layers in this order from top to bottom: aerobic, anoxic, anaerobic.
And this is what I thought it would be too.
But Dr. Ron's article describes it as aerobic, anaerobic, anoxic.
Which one is correct?
Or is it just an issue of nomenclature?
Originally posted by barryhc
Denitrfication is far less well understood by a large portion of the reef keeping community. Very many aquarists still believe that denitrification occurs in the Anaerobic "zone" ( or areas ) of the sand bed, and this is really quite inaccurate. Many aquarists are well versed in this I realize, but many are not, and more so as we look not so far back in time.
The first and most recognized function of denitrification is the reduction of Nitrite into Nitrate and various other results. This process is carried out primarily in a very thin layer or space in the substrate depth.
It need not be vertical either, but it is described in most studies, as occuring in a "layer" as thin as .5mm between the aerobic and anaerobic zones, and "usually occuring at a depth of approx. 5 to 10 mm's deep in fine sediments that are not disturbed by sifting or burrowing animals".
This "zone" has been described with various terms by both hobbyists and experts alike, often times in contradictory fashion, in all directions, and has been the source of an unbelieveable amount of confusion.
I know this for sure, from all the research I've done trying to understand it myself, and the only terms that are not confused in this regard, are "low oxygen", and "Hypoxic".
I like the "low oxygen" term myself, because you just can't confuse that term.
In the "low oxygen" environment, NON-OBLIGATE ( faculative ) Anaerobic bacteria are responsible for reducing Nitrite to Nitrate and other compounds, and this occurs in a ( usually ) very thin layer as stated before.
How thin is this layer actually, especially when "disturbed" or modified by sifting and burrowing animals? I don't know, after 14 mos. of investigation, I'm still trying to find out.
It is now below this "low oxygen" zone, that other processes are carried out by OBLIGATE Anaerobic bacteria, and it is here where Nitrates and other nutrients and compounds are processed into nitrogen gas supposedly, which is somewhat controversial for some reason, and hydrogen sulfide ( again contrversial ), Phosphates "bind and leach", heavy metals "sink", and again, guess what, all controversial.
I believe that all these processes occur in a deep sand bed, to one degree or another, and likely, different in every tank. It is the DIFFERENT in every tank part that has gotten us into this discussion, I'm sure, along with many other things.
I've gotten "long winded" again, not really intending to do so, sorry about that. And I'm no expert, but these again are my observations from very much research.
By the way, algal mats, "binding and leaching", clumping, "sinking", and sifting and burrowing critters, can all be dealt with using a bit of consideration IMO.