Dsb's work, what makes them work best?

[bertoni]

<a href=showthread.php?s=&postid=6476327#post6476327 target=_blank>Originally posted</a> by barryhc
Carib sea has Araganite at .1 to 1mm, and .1mm is within the range of "mud". Is there a reason why we "need" finer substrates than this in the tank?

Thanks > barryhc

Which product goes down to 0.1? That's pretty close. I haven't seen one that fine.

 

[barryhc]

Re: Definitions!

Re: Definitions!

<a href=showthread.php?s=&postid=6476750#post6476750 target=_blank>Originally posted</a> by Acipenser
I think we need to clear up a few things. People are using a few words incorrectly which may be leading to some confusion.

nitrification- the reduction of ammonia to nitrate by nitrosomonas and nitrobacter bacteria. (requires oxygen)

denitrification - the removal of nitrogen compounds by the conversion of nitrate to nitrogen gas. (does not require oxygen)

Well this is the classic understanding, but it is not very accurate.

Faculative Non-obligate anaerobic bacteria BEGIN the denitrification process in the "hypoxic" ( low oxygen ) zone of the sand bed, which is very thin, and easily disturbed, by vacuuming, siphoning, stirring, etc..

Please avoid the term Anoxic as it was introduced by Bob Goemans, for describing low oxygen, as it is incorrect, and causes a tremendous amount of confusion and controversy.

The dentrification process is COMPLETED in the Anoxic ( devoid of oxygen ) zone of the sand bed, or elsewhere. It is this area of the sand bed where nitrogen gas, and Hydrogen Sulfide, and heavy metals accumulation, either do, or do not, occur.

With a couple of definitions, now in order, . . . .

> barryhc

 

[bertoni]

<a href=showthread.php?s=&postid=6476399#post6476399 target=_blank>Originally posted</a> by SDguy
Isn't this contrary to the idea of keeping flow high and particle size small to prevent actual particulates from entering the bed itself?

I don't follow. I'm talking about movement of water within the sandbed, not on top of it.

 

[joefish]

<a href=showthread.php?s=&postid=6476776#post6476776 target=_blank>Originally posted</a> by barryhc
If your husbandry skills were being upgraded significantly enough to mention it here, then maybe it was too late, or not enough algae eaters, or not enough sand "stirrers", or . . . .
I treid to folow all the DSB rules with critters.I bought charging kits , fire wormsspighetti worms , cucumbers lots of snails.I think upgrading signifcantly is an overstatemnet . I was uo to 15-20% weekly water changes , using phosban feeding so much less . The when I did the change over I was able to cut back the water changes and feed three time the amount . which I don't think feeding 6 fish should be considered a heavy Bio-load .





Like critter populations, or "mud" in your filter.

Reef tanks are not defined as SPS dominated. Many SPS are touchy about nutrients, and many are not as much so.

I was talking stonies not just SPS's , although some LPS are more forgiving ..

Many long term DSB tanks have healthy populations of all types of SPS.
true , that I thought was the whole purpose of the thread . But algae will still be a sign of to much nutirents ..

> barryhc

.

 

[bertoni]

<a href=showthread.php?s=&postid=6476771#post6476771 target=_blank>Originally posted</a> by tsquad
An aragonite sand bed (CaCO3) will turn into a brick for one (or both) of these two reasons:
2. Your grain sizes are irregular.

This part I don't understand. Can you elaborate? I don't see how grain irregularities matter, per se.

 

[inwall75]

Re: Diffusion!!!

Re: Diffusion!!!

<a href=showthread.php?s=&postid=6476985#post6476985 target=_blank>Originally posted</a> by Acipenser
I think we all need to get a better handle on the process of diffusion.

Definition: Movement of a fluid from an area of higher concentration to an area of lower concentration. Diffusion is a result of the kinetic properties of particles of matter. The particles will mix until they are evenly distributed.

Any dissolved compound will be evenly distributed throughout the water column. When you reduce nitrates in one area (DSB), nitrate will "flow" to that area to equalize the concentration. A sand bed is no obstacle to diffusion. A semi-permeable membrane - yes, sand - no.

The point is that the organic matter does not have to get into the bed to be processed. The organic matter can be broken down anywhere by any creature. It will be converted to ammonia. Ammonia can be processed anywhere two species of bacteria can colonize (glass, pipes, live rock, sand, etc...) and oxygen is present (alkalinity must be present too, but that is another story). The nitrate will get to the lower areas of the DSB (bucket or in tank) no matter what!

I also feel that diffusion is sufficiently fast to work for denitrification in a DSB.

I would say that nitrification can occur quickly...denitrification is a little slower. However, what a great post.

 

[barryhc]

<a href=showthread.php?s=&postid=6476986#post6476986 target=_blank>Originally posted</a> by bertoni
Which product goes down to 0.1? That's pretty close. I haven't seen one that fine.

Aragamax Sugar Sized Sand > .1 to 1.0mm

Aragamax Select > .5 to 1.5mm

http://www.carib-sea.com/pages/products/marine/substrate/aragonite.html

I would put at least an inch ( maybe two ) of the "Select" on top for "sandstorm resistance", and then however much of the Sugar Size below for denitrification. Probably at least 3-4 inches for me.

> barryhc

 

[Weatherman]

Re: Diffusion!!!

Re: Diffusion!!!

<a href=showthread.php?s=&postid=6476985#post6476985 target=_blank>Originally posted</a> by Acipenser
The point is that the organic matter does not have to get into the bed to be processed. The organic matter can be broken down anywhere by any creature. It will be converted to ammonia. Ammonia can be processed anywhere two species of bacteria can colonize (glass, pipes, live rock, sand, etc...) and oxygen is present (alkalinity must be present too, but that is another story). The nitrate will get to the lower areas of the DSB (bucket or in tank) no matter what!

However, at least dissolved organic matter has to get into the sand bed in order for denitrification to take place.

For bacteria, nitrate is simply an electron receptor, like oxygen, iron, manganese and sulfate. We need to be careful not to consider nitrate to be a "nutrient", or we would have to consider oxygen to be a "nutrient", also.

 

[joefish]

Re: Diffusion!!!

Re: Diffusion!!!

<a href=showthread.php?s=&postid=6476985#post6476985 target=_blank>Originally posted</a> by Acipenser
I think we all need to get a better handle on the process of diffusion.

Definition: Movement of a fluid from an area of higher concentration to an area of lower concentration. Diffusion is a result of the kinetic properties of particles of matter. The particles will mix until they are evenly distributed.

Any dissolved compound will be evenly distributed throughout the water column. When you reduce nitrates in one area (DSB), nitrate will "flow" to that area to equalize the concentration. A sand bed is no obstacle to diffusion. A semi-permeable membrane - yes, sand - no.

The point is that the organic matter does not have to get into the bed to be processed. The organic matter can be broken down anywhere by any creature. It will be converted to ammonia. Ammonia can be processed anywhere two species of bacteria can colonize (glass, pipes, live rock, sand, etc...) and oxygen is present (alkalinity must be present too, but that is another story). The nitrate will get to the lower areas of the DSB (bucket or in tank) no matter what!

I also feel that diffusion is sufficiently fast to work for denitrification in a DSB.

I agree with Inwall , great post .

I understood most of it , I'm still missing how the no3 gets to and through the low oxgen area of sand fast enough to make a difference in the overall tank water .

 

[tsquad]

<a href=showthread.php?s=&postid=6477026#post6477026 target=_blank>Originally posted</a> by bertoni
This part I don't understand. Can you elaborate? I don't see how grain irregularities matter, per se.

Well, not necessarily grain irregularities pertaining to size, but shape. Jagged, nonspherical sand grains will definitely be more probable to compact and lock together than spherical grains. You want different sized grains, but not different shapes, that's my understanding.

 

[inwall75]

Re: Re: Diffusion!!!

Re: Re: Diffusion!!!

<a href=showthread.php?s=&postid=6477194#post6477194 target=_blank>Originally posted</a> by Weatherman
However, at least dissolved organic matter has to get into the sand bed in order for denitrification to take place.

For bacteria, nitrate is simply an electron receptor, like oxygen, iron, manganese and sulfate. We need to be careful not to consider nitrate to be a "nutrient", or we would have to consider oxygen to be a "nutrient", also.

Quite true. I purposely labeled bacteria "food" like I just did in the sentence. It was in quotes.

 

[aubee91]

<a href=showthread.php?s=&postid=6476974#post6476974 target=_blank>Originally posted</a> by inwall75
There are bacteria that are motile and run around in the water column. However, they are the rarity compared to most bacteria that are living in biofilms everywhere else.

If water is passing by a bacterium that contains ammonia or Nitrite, then they want to process whatever hits them. Not all of these bacteria are in a sandbed. Some are in LR and some are on the walls of your aquarium, etc. Electron exchange happens pretty quickly and is actually not done on purpose...it's strictly chemical.

EDIT: Here's a great read. http://www.sp.uconn.edu/~terry/Common/respiration.html

Okay, let me ask this...when nutrient containing particles (detritus, food, whatever) "rot" and are converted to ammonia by aerobic bacteria, where do the phosphates that were also in those particles go? Are they bound up in the bacteria themselves at that point in time? They have to go somewhere but it's not necessarily into the water column though, right?

I'm assuming that in a properly funtioning (and I'm using this term to denote DSB's that have worked for a long time without failing) DSB, the nutrient containing particles are simply eaten by the infauna, when are eaten by other smaller infauna, etc. until the little remaining P is sunk in the bacteria in the DSB. If this is not the case, if I'm misunderstanding how a properly functioning DSB works, then where does that phosphate go?

 

[barryhc]

<a href=showthread.php?s=&postid=6477010#post6477010 target=_blank>Originally posted</a> by joefish
true , that I thought was the whole purpose of the thread . But algae will still be a sign of to much nutirents .. .

"Problem amounts" of algae are a problem.

"Zero algae" is not a requirement.

Each tank and it's inhabitants have different requirements.

There is no "magic bullet", and the whole system either works or it doesn't.

Obviously, the aquarist himself is a part of the system. Each of us will have different energy levels to expend on pre setup research, setup effort and cost, routine maintanence incl. cost, etc. etc. .

The amount of allowable algae and whether it is a sign in a reef tank, will vary.

Thanks > barryhc

 

[inwall75]

Re: Re: Diffusion!!!

Re: Re: Diffusion!!!

<a href=showthread.php?s=&postid=6477204#post6477204 target=_blank>Originally posted</a> by joefish
I agree with Inwall , great post .

I understood most of it , I'm still missing how the no3 gets to and through the low oxgen area of sand fast enough to make a difference in the overall tank water .

That's why I said nitrification is quite quick but denitrification is a little slower. Diffisusion takes some time and bioturbation makes it happen quicker. It will still happen...it's all a matter of timing.

 

[SDguy]

<a href=showthread.php?s=&postid=6477000#post6477000 target=_blank>Originally posted</a> by bertoni
I don't follow. I'm talking about movement of water within the sandbed, not on top of it.

Right, but when you said, "No processing of solid wastes as desired, etc. " This is not desirable, is it? The whole point of flow and small grain size is to keep "solid waste" (and its assumed accompanying phosphates) out of the sandbed. Is this not the case?

 

[Weatherman]

Proximity also helps.

If you can get nitrate created very close to where it's used, it makes the whole process go a lot faster.

 

[SDguy]

Re: Re: Re: Diffusion!!!

Re: Re: Re: Diffusion!!!

<a href=showthread.php?s=&postid=6477276#post6477276 target=_blank>Originally posted</a> by inwall75
That's why I said nitrification is quite quick but denitrification is a little slower. Diffisusion takes some time and bioturbation makes it happen quicker. It will still happen...it's all a matter of timing.

I know Calfo had some anecdotal data regarding various remote DSB setups and how long it then took to begin lowering/completely deplete nitrate.

 

[inwall75]

<a href=showthread.php?s=&postid=6477253#post6477253 target=_blank>Originally posted</a> by aubee91
Okay, let me ask this...when nutrient containing particles (detritus, food, whatever) "rot" and are converted to ammonia by aerobic bacteria, where do the phosphates that were also in those particles go? Are they bound up in the bacteria themselves at that point in time? They have to go somewhere but it's not necessarily into the water column though, right?

Correct. Don't ever try to get into a speed-eating contest with a bacterium....you'll lose.

I'm assuming that in a properly funtioning (and I'm using this term to denote DSB's that have worked for a long time without failing) DSB, the nutrient containing particles are simply eaten by the infauna, when are eaten by other smaller infauna, etc. until the little remaining P is sunk in the bacteria in the DSB. If this is not the case, if I'm misunderstanding how a properly functioning DSB works, then where does that phosphate go? [/B]

Most of it stays there for quite some time. It's recycled because bacteria are cannibals. Eventually, other things happen but lets not go there yet.

 

[joefish]

<a href=showthread.php?s=&postid=6477274#post6477274 target=_blank>Originally posted</a> by barryhc
"Problem amounts" of algae are a problem.

"Zero algae" is not a requirement.

Each tank and it's inhabitants have different requirements.

There is no "magic bullet", and the whole system either works or it doesn't.



The amount of allowable algae and whether it is a sign in a reef tank, will vary.

Thanks > barryhc

Maybe we should discuss whats exceptable amounts then .

how much in a sps tank ?

how much in a LPS tank ?

How much in a softy tank ?

How much in three way mix ?

No I don't believe a tank can have zero algae , but let's talk about when it is a problem . Obviuosly a large amount will have to do with what animals you are keeping .

Obviously, the aquarist himself is a part of the system. Each of us will have different energy levels to expend on pre setup research, setup effort and cost, routine maintanence incl. cost, etc. etc. .

This also should help decied on which kind of corals one wants to keep .


I'm hoping some one will still answer this for me .

PS; Reefers who have DSB working correctly , when you see algae starting to form , how do you know when it's just a fauna cycle or a sign of a bigger problem ?

 

[tsquad]

<a href=showthread.php?s=&postid=6477382#post6477382 target=_blank>Originally posted</a> by joefish
I'm hoping some one will still answer this for me .

Joe, I don't know if this'll help, but since I cooked my rock and upped my SSB from 3" to a 6" DSB, I haven't had ANY nuisance algae growth. Just coralline, and I use my Magfloat once or twice a week, just to keep the glass as clear as possible.

Before doing this, I had hair algae pockets, valonia all over, and had to clean the glass every two days at least.