New Nitrate theory

[tmz]

No need for acrimony;it detracts from discussion more than any position a person may take.

Sand is just sand and not worth hard feelings.

It is good at providing a lot of surface area for bacteria to colonize in a relatively small space as compared to other substrates or even live rock. I don't think it necessarily clogs if sand critters are maintained. Without them movement of nutrients and detritus as well or any organic carbon source for bacteria just won't happen so there may not be anything downt there to feed bacteria or to rot.

Much of the new thinking on dsbs is that a good deal of denitrification may occur in the first inch or two of sand bed obviating the need for greater depth purely for denitrification.

I have a 7 yr old dsb and several shallow bed tanks and a bare bottom. In my opinion they all can work. Deep beds do provide habitat for certain fishes and other critters and microfuana not available in shallow or bare bottom tanks. They also provide enhanced surface areas and require some maintenance.

It is largely a matter of personal choice and aesthetic preference and the critters you want to keep.

 

[jenglish]

I do know of a few long running DSBs that are ran with ATS systems. I think one of the problems with saying a technique will or won't work based an example is these are complex systems. There are so many variables involved. Do the DSBs I know of work because of their depth, the microfauna involved.... or is it the ATS..... or is it the sheer volume of the system providing stability (I am thinking of the system at Inland Aquatics in Terre Haute IN).

I think DSBs can be a benefit. I think they need to be cleaned just like any other substrate. You can and in my opinion should vacuum a DSB, even one with oolitic aragonite. It still gets poop in it You shouldn't do it all at once like some may do with CC or gravel... but removing unbroken down detritus can remove things before they are bound up PO4.

It does make me wonder about a silcate DSB.... could this offer the benefits of DSB w/o the ability to bind up PO4?

 

[Paul B]

Capn, it was never a fight, just an enlightening conversation by a member. I am hoping we will hear more from Whys.

Much of the new thinking on dsbs is that a good deal of denitrification may occur in the first inch or two of sand bed obviating the need for greater depth purely for denitrification.

I totally agree with this. A DSB a few inches deep should work fine. I don't think some of those 6" beds will fare so well. They may sit there for years and not cause any harm but I doubt the lower layers are doing anything except take up space.

Also it is true (as was said) that these systems are much too variable to say what will and will not work. I am mainly going on the amount of people in the hobby and the length of time various systems last. I think a SSB or BB should last the longest but they also have the least capacity to control nitrates and this task will need to be performed some other way.
Again, I never said DSBs don't work. I said I don't think they will last for long. I am older than most here and ten years is not a long time to me. Almost all fish live twice that length of time.

I love these exchanges of information and never consider any of them a fight.

 

[jasonrp104]

I must've misunderstood somewhere in my reading. I was under the assumption that for the most part DSBs needed to be left undisturbed BUT to help with thier longevity, it was good to jam holes in them once in awhile.

Every other water change, I'll take my turkey baster and stab my sandbed right to the glass in a few random areas. I figured yes, it would kill some bacteria but it would also help keep the deeper parts from becoming too nasty. My sandbed is relatively new but it is already de-nitrifying and full of critters. Should I stop? To me, it makes sense to do it

 

[herring_fish]

Water Chemistry

Water Chemistry

Ok We talk about reducing nutrients with sand deep beds but what about their ability to stabilize water chemistry? I am re-staring a tank after a long layoff and am having problems with my pH, KH and calcium etc. My old tank had a plenum, 3” of coral gravel, 4” of coral sand and live rock. I also used an Algal Turf Scrubber (ATS).

With this set up, I never had any problems of any kind, once it matured. This time I have the same ATS but I have been playing around with different sand configuration, varying from almost nothing to having 8” of gravel in a 55 G sump and back again. I reached the point of stability much faster in my old tank, than the time that I have invested in my new one and it hasn’t come yet.

I know that stirring up large amounts of sand can cause wild fluctuations in water chemistry and I can now attest to that. Since I have an ATS, I don’t worry about nutrients. I have never had any test read anything above zero in my old tank and the same is true of the new one. My old tank never ran very high calcium or pH levels like I was dosing but it never tested low. It was always completely stable, no mater how much I feed the tank or how inconsistently I did so.

Therefore I wonder how best to construct a bed to maximize the desolation of aragonite. I really can’t say how well my old sand bed processed nutrients. Regardless of whether my old sand bed was of optimal design, it seems to have become the source great stability for 8 years.

So if I don’t care about nutrients, what should I do?

 

[jenglish]

<a href=showthread.php?s=&postid=14933459#post14933459 target=_blank>Originally posted</a> by jasonrp104
I must've misunderstood somewhere in my reading. I was under the assumption that for the most part DSBs needed to be left undisturbed BUT to help with thier longevity, it was good to jam holes in them once in awhile.

Every other water change, I'll take my turkey baster and stab my sandbed right to the glass in a few random areas. I figured yes, it would kill some bacteria but it would also help keep the deeper parts from becoming too nasty. My sandbed is relatively new but it is already de-nitrifying and full of critters. Should I stop? To me, it makes sense to do it

THere are those that believe you should never disturb a DSB and those who think they need to be regularly vacuumed.

 

[Bri Guy]

I think this is a great thread, but have a question.

So far the discussion has all been from an experience view, what about the actual chemistry here.

NH₄ turns into NO₃ which then turns into NO₂ this we know, but then thats where the road splits.

Chemically what are the 2 they are turning into? Does one bacteria take one more oxygen and make nitrogen gas? and the other bacteria takes the rest of the oxygen away and adds hydrogen back to make NH₄ ?

Can anybody verify what the bacteria are doing chemically at the road split?

thankx

 

[gasman059]

nice thread Paul

nice thread Paul

I not only agree wholeheartedly but have experience DSB issues in the past.

It is not how but when an older tank with a true DSB(4-5) will crash since we don't really stay on top of it.

No difference that a UG filter(I've used them) it too will fail if factors such as feeding, flwed circulation, meds,and gravel cleaning are not performed religiuosly.

Natural nitrate reduction thru a DSB is IMHO a thing of the past- if that will and is gonna be an issue in your future tanks u should consider another denitrification process from the get go such as a reactor.

Recent tank includes a 1-2 inch large grain media.

 

[Paul B]

I think we will always have NNR but we will get better at it.
For now there is no perfect system, the bacteria have a mind of their own and don't always want to help us.

 

[Aquarist007]

Re: nice thread Paul

Re: nice thread Paul

<a href=showthread.php?s=&postid=14936650#post14936650 target=_blank>Originally posted</a> by gasman059
I not only agree wholeheartedly but have experience DSB issues in the past.

It is not how but when an older tank with a true DSB(4-5) will crash since we don't really stay on top of it.

Sorry for asking such a basic question as I probably reach your kneee caps with experience compared to you guys.
My deep sand bed is relatively new(2.5 years) and I have not done any maintenance on it other then to adjust flow rates through the refugium.
What should I be doing to "stay on top of it"

 

[Paul B]

What should I be doing to "stay on top of it"

Try not to live too long and it will be fine :lol:

It is not even 3 years old so it should be fine for 7 more years as far as I can tell.

 

[Aquarist007]

<a href=showthread.php?s=&postid=14937234#post14937234 target=_blank>Originally posted</a> by Paul B
Try not to live too long and it will be fine :lol:

It is not even 3 years old so it should be fine for 7 more years as far as I can tell.

great --it can be someone elses problem by then---I'll probably have moved on to the tank in the sky:lol:

 

[Paul B]

I'll probably have moved on to the tank in the sky

And I will be right next to you.
I wonder if they only let you keep "Angel Fish" in heaven :lol:

Probably no Blue Devils :eek1:

 

[Aquarist007]

<a href=showthread.php?s=&postid=14937393#post14937393 target=_blank>Originally posted</a> by Paul B
And I will be right next to you.
I wonder if they only let you keep "Angel Fish" in heaven :lol:

Probably no Blue Devils :eek1:

Sorry to be the bearer of bad news but I don't think you will be allowed in there----not with all the sea food you have "forked" speared or swallowed whole in your life:lol: :rollface: :lol:

 

[tmz]

<a href=showthread.php?s=&postid=14936415#post14936415 target=_blank>Originally posted</a> by Bri Guy
I think this is a great thread, but have a question.

So far the discussion has all been from an experience view, what about the actual chemistry here.

NH₄ turns into NO₃ which then turns into NO₂ this we know, but then thats where the road splits.

Chemically what are the 2 they are turning into? Does one bacteria take one more oxygen and make nitrogen gas? and the other bacteria takes the rest of the oxygen away and adds hydrogen back to make NH₄ ?

Can anybody verify what the bacteria are doing chemically at the road split?

thankx

I don't think the road splits on the chemistry of denitrifiction as it does on wether deep sand beds provide suitable long term anoxic environments for the heterotrophic bacteria that perform it .
The chemistry is the same wether denitrifiction occurs in a shallow bed or a deep one, The debate is about where it will most efficiently occur
As you may know, these bacteria in the absence of O2 turn to the O3 in NO3 for energy . The end product is harmless free nitrogen gas which returns to the athmosphere or may be fixed back into an organic form . Cyanobacteria can fix nitrogen for example .It seems this notion of a new nitrate theory is based on the assumption that some new formerly unknown strain of bacteria may exist that fixes this free nitrogen.

 

[Aquarist007]

<a href=showthread.php?s=&postid=14937663#post14937663 target=_blank>Originally posted</a> by tmz
I don't think the road splits on the chemistry of denitrifiction as it does on wether deep sand beds provide suitable long term anoxic environments for the heterotrophic bacteria that perform it .
The chemistry is the same wether denitrifiction occurs in a shallow bed or a deep one, The debate is about where it will most efficiently occur
As you may know, these bacteria in the absence of O2 turn to the O3 in NO3 for energy . The end product is harmless free nitrogen gas which returns to the athmosphere or may be fixed back into an organic form . Cyanobacteria can fix nitrogen for example .It seems this notion of a new nitrate theory is based on the assumption that some new formerly unknown strain of bacteria may exist that fixes this free nitrogen.

Tom---can you point me to some readings on this?

 

[gasman059]

The chemistry is the same wether denitrifiction occurs in a shallow bed or a deep one, The debate is about where it will most efficiently occur

this should help.
http://www.reefkeeping.com/issues/2008-06/newbie/index.php

 

[Paul B]

Sorry to be the bearer of bad news but I don't think you will be allowed in there----not with all the sea food you have "forked" speared or swallowed whole in your life

In California we had the best barbecued oysters I have ever eaten. From now on, they will be on my plate more often.

OK back to the topic

 

[Bri Guy]

<a href=showthread.php?s=&postid=14937663#post14937663 target=_blank>Originally posted</a> by tmz
I don't think the road splits on the chemistry of denitrifiction as it does on wether deep sand beds provide suitable long term anoxic environments for the heterotrophic bacteria that perform it .

Im actually quoting the artical here...

Quote:
The resulting nitrate
is then acted upon in a lower area of
the substrate that contains little or no
oxygen, generally referred to as the
anaerobic area. It is there that we found
two different classes of bacteria following
two different pathsâ€"one path reducing
nitrate to ammonium only (the primary
alga nutrient), and the other reducing it
to nitrogen.
UnQuote:

It says that one reduces NO₂ to NH₄ and one turns it into nitrogen.

And thats the spin on this artical, Is nitrate actually turned back into ammonium???

 

[tmz]

That's the split in the road. Does this second type of bacteria really exist in a deep sand bed? BTW Here's the second paragraph of my post.

As you may know, these bacteria in the absence of O2 turn to the O3 in NO3 for energy . The end product is harmless free nitrogen gas which returns to the athmosphere or may be fixed back into an organic form . Cyanobacteria can fix nitrogen for example .It seems this notion of a new nitrate theory is based on the assumption that some new formerly unknown strain of bacteria may exist that fixes this free nitrogen.