DIY Sulfur Denitrator
- Thread starter JohnL
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Belgian Anthias
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growing macroalgae : needs a lot of space, must be harvested regularly, risk for sudden die off and the risk for toxics. Effluent must be sterilized because the may become part of your display and overgrow everything if there is enough food (nitrate).
organic carbon dosing (vodka, vinegar, pellets, etc): very dangerous because all kind of bacteria are cultivated and fed, also toxic ones, difficult to dose and manage with bacteria bloom and or sudden die off with relief of toxics.
live rock and/or sand or porous media/ The best method available if enough place and the dicipline needed not to overcrowd the system is brought up.
skimming and other ways to remove organics before they degrade: is not an de-nitration method. Avoiding waste buildup is good management. Stripping the water completely is not.
If the system is in good balance a de-nitrator is not necessary!
But fish and corals grow and animals multiply.
Belgian Anthias
New member
Your explanation is correct. When the flow becomes TO high!
But wrong way of thinking. That is why the reactor must be big enough. When increasing the flow more oxygen, nitrate and carbon becomes available and less bacteria will be anaerobic active. So adjustments must be made by little increments.
If the reactor is not big enough, the point of balance can not be found.
After increment is made some nitrite may be formed but this is not dangerous because the effluent is aerated. Wait some time to give the bacteria some time to adapt to the situation. if no nitrite is noticeable any more increase a little bit more and so on. When nitrite does not disappear after a few hours lower the flow a little bit. Once balance is found corrections have only to be made when changes in the system setting are made.
This is experienced with 1% reactors. When the reactor is to small it may be balance can not be found.
A normal functioning 1% reactor will have a flow between 2% and 5% of the system volume but can also function between 2% and 10%. Which means system water is filtered once to twice a day. If the flow becomes less than 2%, except during start up and incubation, something should be wrong.
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growing macroalgae : needs a lot of space, must be harvested regularly, risk for sudden die off and the risk for toxics. Effluent must be sterilized
Seems pretty extreme. Do you know a single person who does that? I certainly don't.
very dangerous because all kind of bacteria are cultivated and fed, also toxic ones
Ever seen a case where a toxic bacteria driven by organic carbon dosing caused a clear problem? IMO, this is a "potential" risk that seems to not be real.
Thiobacilllus denitrificans function well in aerobic and anaerobic conditions.
I don't disagree, but since you mention it a lot, do you have evidence that this is the primary species that grows on a reef tank sulfur denitrator?
Seems pretty extreme. Do you know a single person who does that? I certainly don't.
very dangerous because all kind of bacteria are cultivated and fed, also toxic ones
Ever seen a case where a toxic bacteria driven by organic carbon dosing caused a clear problem? IMO, this is a "potential" risk that seems to not be real.
Thiobacilllus denitrificans function well in aerobic and anaerobic conditions.
I don't disagree, but since you mention it a lot, do you have evidence that this is the primary species that grows on a reef tank sulfur denitrator?
Thiobacilllus denitrificans function well in aerobic and anaerobic conditions.
Glad you got that. I've been saying it right along.The aerobic activity is undesireable IMO.See post #1250
All living things do not need oxygen. some do.
Never said all living things need oxygen,.Why are you bringing that up?
Thiobacillus denitrificans,the bacteria you claim is the primary sulfur bacterial species at work, don't need oxygen , for example, as I've explained. When they have oxygen available they use it but don't reduce nitrate to N and N2 ; they just use the oxygen to oxidize the sulfur ; get their energy from that process and produce SO4 and organic material ;not a good thing IMO.
Increasing the flow when nitrate in the tank is zero puts more oxygen in the reactor and they will use it.they don't need the nitrate when oxygen is available.
Reducing the amount of sulfur available will limit these facultative sulfur bacteria ;increasing the flow of aquarium water won't.
Glad you got that. I've been saying it right along.The aerobic activity is undesireable IMO.See post #1250
All living things do not need oxygen. some do.
Never said all living things need oxygen,.Why are you bringing that up?
Thiobacillus denitrificans,the bacteria you claim is the primary sulfur bacterial species at work, don't need oxygen , for example, as I've explained. When they have oxygen available they use it but don't reduce nitrate to N and N2 ; they just use the oxygen to oxidize the sulfur ; get their energy from that process and produce SO4 and organic material ;not a good thing IMO.
Increasing the flow when nitrate in the tank is zero puts more oxygen in the reactor and they will use it.they don't need the nitrate when oxygen is available.
Reducing the amount of sulfur available will limit these facultative sulfur bacteria ;increasing the flow of aquarium water won't.
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The reactor will not and may not become anoxic at low nitrate levels.
I don't understand what that means; are you saying it will or won't: will it or may it?
Part of them will use the available carbon
Which part ? Thiobacillus deniotrificans don't use organic carbon for energy, they use sulfur for that .They are chemolithoautotrophs and get there organic carbon they need for biomass from CO2.
If a sulfhur de-nitrator is managed wrong and the amount of sulfhur is based on the amount nitrate available flow management becomes impossible
I disagree, sizing the amount of sulfur to the amount of nitrate reduction needed on an ongoing basis to handle whatever denitrification need the aquarium isn't handling through other bacterial actvity and nitrate reduction methods along with manipulations in flow makes sense to me as part of managing a denitrator properly Most folks start using a sulfur denitrator to reduce accumulated high nitrate levels . Once that initial reduction occurs ,the ongoing excess nitrate production from an aqaurium is likely to require less nitrate reduction by the sulfur bacteria. Less sulfur = less sulfur bacteria.
This way a state where hypoxic conditions favorable to the desireable anaerobic activity can be maintained by balancing flow to reduce the chance for anoxia and hydrogen sulfide production while aerobic activity can be limited by less flow and less sulfur as it limits the sulfur reducing bacteria in action by limiting their energy source.
I don't understand what that means; are you saying it will or won't: will it or may it?
Part of them will use the available carbon
Which part ? Thiobacillus deniotrificans don't use organic carbon for energy, they use sulfur for that .They are chemolithoautotrophs and get there organic carbon they need for biomass from CO2.
If a sulfhur de-nitrator is managed wrong and the amount of sulfhur is based on the amount nitrate available flow management becomes impossible
I disagree, sizing the amount of sulfur to the amount of nitrate reduction needed on an ongoing basis to handle whatever denitrification need the aquarium isn't handling through other bacterial actvity and nitrate reduction methods along with manipulations in flow makes sense to me as part of managing a denitrator properly Most folks start using a sulfur denitrator to reduce accumulated high nitrate levels . Once that initial reduction occurs ,the ongoing excess nitrate production from an aqaurium is likely to require less nitrate reduction by the sulfur bacteria. Less sulfur = less sulfur bacteria.
This way a state where hypoxic conditions favorable to the desireable anaerobic activity can be maintained by balancing flow to reduce the chance for anoxia and hydrogen sulfide production while aerobic activity can be limited by less flow and less sulfur as it limits the sulfur reducing bacteria in action by limiting their energy source.
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A normal functioning 1% reactor will have a flow between 2% and 5% of the system volume but can also function between 2% and 10%. Which means system water is filtered once to twice a day. If the flow becomes less than 2%, except during start up and incubation, something should be wrong.
Those %s may work for you but not others.Nitrate production will vary in different aquariums. Each aquarist needs to find the balance of flow and sulfur mass suited to the specific aqariums ongoing need for nitrate reduction from the denitrator,IMO.
Those %s may work for you but not others.Nitrate production will vary in different aquariums. Each aquarist needs to find the balance of flow and sulfur mass suited to the specific aqariums ongoing need for nitrate reduction from the denitrator,IMO.
Belgian Anthias
New member
Again, the amount of Nitrate may not have influence in the amount of sulfhur. The % rule works for all aqua. Only when the aqua is overcrowded and or Nitrate is above 50 ppm one may consider to use a 2% reactor for fish only tanks. The balance is found by adjusting the flow! It is very simple, less nitrate, more flow and visa versa. If the reactor is not big enough balance will not be found resulting in a not or bad working reactor!
Belgian Anthias
New member
There are not only autotropic bacteria in the aquarium water that enters the reactor.
Again, the amount of active aneorobic bacteria is regulated by the flow, the amount of oxygen entering the reactor. The amount of sulphur is in no relation to the amount of active bacteria, there is always enough to feed them for many years! If the reactor is to small balance can not be found and managing the reactor becomes impossible.
Your way of thinking will not reduce the amount of active bacteria, it will kill the bacteria which body's die off and produce sulfide due to self created anoxic conditions; The produced sulfide in a sulphur reactor is rarely a product of the sulphur but mostly caused by the decay of the biomass from the dead bacteria due to bad management.
Belgian Anthias
New member
Yes, that is how the reactor should be managed; In an aquarium with animals there will always be some nitrate production; Increasing the flow will bring more nitrate to the bacteria but will decrease the anaerobic activity; This way balance can be found.
Reducing the sulfhur to a level that has influence the amount of active Thiobacillus denitrificans will create problems that or not manageable any more and kill the beast! That is why a lot of people find a sulphur de-nitrator difficult or impossible to manage. Wrong way of thinking.
How the flow can be managed if only a few drops effluent are produced? Impossible.
A sulphur de-nitrator should work continuously, also when nitrate is very low.
If nitrate is 0 a de-nitrator has no use.
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Belgian Anthias
New member
growing macroalgae : needs a lot of space, must be harvested regularly, risk for sudden die off and the risk for toxics. Effluent must be sterilized
Seems pretty extreme. Do you know a single person who does that? I certainly don't.
very dangerous because all kind of bacteria are cultivated and fed, also toxic ones
Ever seen a case where a toxic bacteria driven by organic carbon dosing caused a clear problem? IMO, this is a "potential" risk that seems to not be real.
Thiobacilllus denitrificans function well in aerobic and anaerobic conditions.
I don't disagree, but since you mention it a lot, do you have evidence that this is the primary species that grows on a reef tank sulfur denitrator?
Will become your problem some day. Instead of macro algae use Halimeda; You can feed it to the animals.
VODKA, it works but don't say you where not warned.
Sulpur-denitrators where lab tested and used in public aquaria for a long time. Everything about the working is known.
http://genome.jgi-psf.org/thide/thide.home.html
http://filebox.vt.edu/users/chagedor/biol_4684/Cycles/Soxidat.html
http://mars.reefkeepers.net/USHomePage/USArticles/Soler/DenitratorSoufre.html
THE AUTOTROPHIC DENITRATATION ON SULFUR - WHAT'S THE STATUS?
http://mars.reefkeepers.net/USHomePage/USArticles/SulphurDenitrator.htm
http://www.masa.asn.au/phpBB3/viewtopic.php?f=55&t=249607l]
ref:Congrès E.U.A.C., Munich, Salzbourg & Innsbruck 1996
Mém. Inst. Océano. P. Ricard 1997, pp: 7-13
ELIMINATION DES NITRATES PAR FILTRATION
BIOLOGIQUE AUTOTROPHE SUR SOUFRE EN
AQUARIOLOGIE MARINE
Michel HIGNETTE,* Benoit LAMORT,* Marc LANGOUET,** Sébastien LEROY* et Guy MARTIN***
* Aquarium du MAAO - 293, Av. Daumesnil, 75012 Paris
** Le Grand Aquarium - La Ville Jouan - Av. du Général Patton, 35400 Saint Malo
*** Laboratoire Chimie des Nuisances et Génie de l'Environnement ENSCR - Av. du Général Leclerc, 35700 Rennes
THE AUTOTROPHIC DENITRATATION ON SULFUR
WHAT'S THE STATUS?
Last update: 12/01/99
By Marc LANGOUET ing ENSCR, Translated by Nicolas Will
In a confined space, like the one in an aquarium, the regular addition of food that necessarily contain a quantity, more or less important, of nitrogenous compounds, will, without fault, lead to a level of nitrate incompatible with the inhabitants life.
This phenomenon is now well known by most aquarists, in particular those that maintain reef aquariums. The coral's tolerance regarding nitrates is particularly small compared to other living organisms.
Various solutions were proposed to avoid this problem: water changes, algal turf scrubbers... The most common of all is probably the protein skimmer, pillar of the Berlin Method, which consists in the elimination of a maximum of nitrogenous compounds before they are transformed into nitrates.
However, this method are not without difficulties and do not always allow to easily get rid of the problem. I am mostly thinking about aquariums well or very loaded by fish or about those that are hosting corals or invertebrates needing frequent additions of food (a good number of gorgonians or beautiful corals like Tubastraea aurea, the Dendronephtya family or the Carotalcyon sagamianum).
These beautiful animals are rarely raised in aquariums because of the fact that they need to be very regularly fed (which can be automated), and this leads very quickly to high nitrate levels.
I will explain here the two original methods that I developed and which use could quickly spread.
1. Autotrophic denitratation on sulfur
An article published by MARS (18/5/98) and written by Christophe SOLER gives a good picture of the method. I will just simply give historical precision and further information. It is my ex-professor Guy Martin from Ecole Nationale Supérieure de Rennes who is at the origin of this idea; he applied it to fresh water treatment for public water.
I tested this method with seawater, which was new, especially since we didn't know if it would have toxic consequences for our animals, as soon as 1991.
It is only by the end of 1994, after three years of experiments without apparent toxicity in numerous aquariums and species present at home, that I proposed this method to Michel Hignette, curator of the MAAO aquarium. A pilot project was lunched under my care.
Since then the experiment was done on a much bigger scale, at the MAAO, as well as in the Grand Aquarium in Saint-Malo, of which I was technical and scientific director from June, 1st 1996 to mid-December 1997.
I wish to stress the fact that I am using since 1996 beads of sulfur of a 3.5-mm diameter. This form is much easier to use than bars that you have to break using a hammer.
The quantity of sulfur to use depends on the initial nitrate level at startup and on the amount of food added. I consider that a sulfur volume equal to 1% of the total water volume is enough when the initial level is below 50 mg/l (NO3-).
The water flow that must go through the sulfur column depends on the nitrate level of the water to be treated: the more nitrates, the lower the flow must be, otherwise you will find part of the nitrates will be found after the column.
At startup, you can count on 1 liter per hour and per sulfur liter in the column. Then you can adjust in the following manner:
- If the flow rate is too low, you will get a rotten egg smell at the column's exit due to a production of sulfurous hydrogen (H2S). This will rarely happen for really low flow rates.
- If the flow rate is too high, you will detect nitrites or nitrates in the output water.
- If the flow rate is correct, you should obtain 0 nitrates.
However, experiments show that the system is very tolerant regarding the flow rate, which could go up to 5 liters per hour per sulfur liter.
The water sent to the column could come from a filter derivation or directly from the aquarium. The column must allow the produced nitrogen to escape: for these reason a vertical circulation, from bottom to top, seems a better choice, with a flow-rate setting at the input, not at the output. The column's output can be open to the air. The water exiting the sulfur column can be very acidic, but after my experiments getting the gas out of the water (by using an air-stone for example) allows to get a pH close to the original. The water's acidity is then at least mainly linked to the presence of carbon dioxide; thus the idea to use this water to make a calcium reactor by making it flow in a second (and why not a third) columns, identical in size to the one containing the sulfur, but this time filled with maerl or some coral sand (the same that you are using for your sandbed).
This output water also contains sulfates in quantities slightly higher than at the input, but in 7 year of experiments it has never been observed any consequence, even in aquariums that didn't get any water changes for years. It must be noted about that subject that there was an error in the publication made with the MAAO: the sulfur level in natural seawater is near 900 mg/l; this sulfur is present under the form of about 2.65 g/l sulfate (SO4--), quantity, which by itself can explain that the system's addition in sulfate will be without any notable consequence.
2. Pr. Jaubert's method boosted by sulfur
Pr. Jaubert's method is now more and more known; I've been using it since 1994. It consists in placing nitrates reduction into nitrogen and the calcium reactor directly inside the aquarium. The reduction is done in the lower part of a thick layer (8 to 10-cm) of sand (J. Jaubert pers. comm.). This method works very well; however, it seems limited to aquariums with low fish load, or not fed very often, most probably by lack of organic elements in the sand's lowest part, a limiting factor for anaerobic bacteria development, which transforms nitrates into nitrogen by using carbonated matter (organic matter).
It also seems that only well-lit aquariums can work following this method, even if we don't have any complete explanation yet.
Finally, the substrate's surface that is covered by the rocks must not be over 25% of the total surface (J. Jaubert pers. comm.).
If, for a reason or another, nitrates are persistently present in the water, we can boost the system to make them disappear, faster, by accelerating the bacterial process by introducing organic compounds in the lower layer of sand (glucose, by example, by introducing a tube that penetrates under the layer, the other extremity sticking out of the water in the air).
To push Pr. Jaubert's method beyond its limits, i.e. in a heavily fed or under-lit aquarium, without adding glucose under the sandbed, and still conserve its advantages, i.e. its extreme simplicity, no external reactor, no flow rate to set, incorporated calcium reactor, etc. an idea came to me, a few years ago, to get rid of the limiting factor that is made of the quantity of organic compounds present in the lower layer of sand by boosting the system with a thin layer of sulfur in the form of beads at the same level. This allows the system to work in an autotrophic way instead of a carbon-heterotrophic-only way.
The device that I successfully experimented is made of a traditional floor net, from an under-gravel filter without up-lift (the water flows only naturally through the sand, just like in Pr. Jaubert's method).
I established at the end of August 1998 an experimental protocol.
I completely rebuilt a 100-liters aquarium that was established a few years back with 6 to 8-cm of coral sand and a few live rocks. It must be noted that this aquarium, even if it was setup following the Jaubert principle, had nitrate level rises during feeding periods.
Even empty of any animal and not fed for months, its nitrate level did not diminish. It is the perfect example of a scarcely lit Jaubert aquarium that does not work fast enough, most probably because of a lack of nutrients for the anaerobic bacteria present in the lower layer.
I setup the system by layering sulfur beads between the UGF plate and the sand, 1/2 cm thick, sandwiched between two plastic mosquito nets.
The 65 to 70 liters of water contained 35 mg/l of nitrate (NO3-). I reused this water to fill the new setup. Five days later the aquarium had a nitrite level above 10 mg/l. I was using live sand that was already full of aerobic bacteria. It was the first step of the transformation of nitrate into nitrite using sulfur that was starting, and not the transformation of ammoniac into nitrite like happens traditionally in a newly established tank.
On the tenth day, the nitrite level was of about 1 mg/l; the transformation of nitrite into gaseous nitrogen was on going. In a system of this type, where the water flow is produced by natural diffusion through the sandbed and not forced through a filter, it is logical that the evolution is slower than in systems using reactors.
On the eleventh day no nitrite was left and the nitrite level was below 5 mg/l.
On the Twelfth Day the nitrate level was not measurable at all (below 1 mg/l).
On the 24th day the aquarium was still without any nitrate, even if it received every day a cube of frozen artemias (around 1-cm3), which is pretty high for a 65-liters tank. The Tubastraea aurea in this aquarium for two months was nearly opened all day long, liking the strong water flow in the tank and the daily addition of food. It was the same for some Actinias equina and two Carotalcyon sagamianum specimens. The pH was around 7.7, because of Carbon dioxide present (degassing raises the pH) but this didn't look like it bothered the invertebrates. The KH was between 6 and 7. It was the same as the one from the Channel water that I used to fill the tank.
This very interesting method could perfectly be established in the sump of an existing aquarium so that the whole setup doesn't have to be rebuilt. The low pH will most probably shock some of you, but it should be noted that with Pr. Jaubert's method, the pH and KH are generally lower than those found using the Berlin method (at least in the morning concerning the pH). It is without noticeable consequence for the animals. My aquarium is not lit (only by ambient light in the room). It is not aerated by any other mean than a normal air/water interface, this interface being slowly moved because I preferred to direct current in the direction of the corals to bring then food.
In a lighted aquarium and with a good surface movement, or with an air stone, the dissolved Carbon dioxide should be eliminated in a better way, and the pH should be higher. The sulfur surface may not cover the tankÃs entire surface like I did.
I am personally convinced that this CO2 presence in the water in not necessarily a problem, but time will tell. As soon as I can lay my hands of some Dendronephtyas, gorgonians, Sphaerella krempfis, sponges, etc. I will add them to this aquarium. Feeding should be automated and more regular, simple flakes are enough to open the Tubastraea aurea.
Please send me your experiments in this field.
To be continued...
Marc LANGOUET.
6/11/98
Note 1
Autotrophic: not needing any external energy or nutrients addition
Heterotrophic: needing external energy or nutrients addition
Note 2
You can send your comments or experiments results to
Marc LANGOUET
La Guimorais
35350 St Coulomb
tél.+fax. 02 99 89 41 69 email marc.langouet@wanadoo.fr
or to Récif France Britanny, which will forard
Pierre ZMIRO
17 rue de la gare
49440 Candé
Tél. 02 41 94 92 10
Fax 02 41 94 92 11
E-mail FBZ@wanadoo.fr
Q&A and diverse information
Question: Marc evokes Degassing (escape of produced nitrogen) in his publication. Having no sump for my aquarium, I want to place the column below in the stand; it will then be full of water. I will fill the column with sulfur and maerl (50/50). I want to fix the output in the air, above water surface. Will it be enough for degassing? Can it work like this while being as efficient?
Marc's answer: There is no problem with a column filled with water; the water flow must be from bottom to top of the sulfur maerl column. It must be noted that this mix is not a good idea as the maerl will be transformed into puree with time, and you will have to throw away the whole because it will clog... You should better separate the sulfur and the sand because sulfur can be kept: it doesn't deteriorate.
Question: Must sulfur be regularly added?
Marc's answer: Sulfur is used, but it is very low. It corresponds to
4NO3 + 3S ->2 N2 + 3 SO4
(it is more complex, but it comes to that)
In practice I never added any sulfur in years, even less changed it.
Question: What is the exact use of the air escape? Is it fundamental?
Marc's answer: The air escape is the to help nitrogen getting away, if you work with high nitrate levels. If this level is low, this degassing will be small and I don't think this would be a problem to send this water into a calcium hydroxide reactor. The experiment is left to you.
Question: What is the cost of sulfur?
Marc's answer: Sulfur's cost is about US$2 per kg
Question: I built a reactor following MARS' plan with 2x 5-liters columns; one contains sulfur beads, the other some calcareous substrate. In 8 days, nitrate, which used to be at about 25 mg/l in my 400-liters aquarium, are now at zero at reactor's output. A month after the setup nitrates is between 0 and 5mg/l in the aquarium. It's really working!
But as nothing is easy in reefkeeping, there are other parameters changed by the sulfur reactor.
Calcium was at 410 mg/l before y using limewater as make-up water (5-liters per day, whichÃs low because my tank is closed and using fluos). After a month the level is at 490 mg/l at reactor's output! Great! Is it the substrate column doing anything?
However the pH is from 0.6 to 0.8 lower at reactor's output. In the aquarium it went down from 8.2 to 7.8 in a month (7.05 at reactor's output). How can I cleanly raise the pH without disturbing the animals? Will this pH drop ever stop? Is it because of sulfur denitratation system?
MARS' Answer: The flow rate through the reactor is not given. Maybe you can tweak that (higher or lower) to lower the acid dosing in the aquarium like in a Calcium carbonate/CO2 reactor. Also like in a calcium reactor if the substrate is too big, water flows too fast and doesn't dissolve it and doesn't lose acidity. To correct this, either lengthen the circuit or get finer substrate.
MARS' comments:
This method has now been used for a while by a good number of hobbyists who all saw their nitrates level drop. One thing to look at (beginners beware!) would be, as nitrates consumption is huge, to lower skimming quality (to be kept to remove the compounds not removed by the sulfur reactor?). Plankton would be protected. As the sulfur reactor is making acid, calcium production is allowed by adding a calcium reactor in-line. No more CO2 bottle. A number of question marks are left, but the system is charming! We can imagine small autonomous aquariums, but why not also large (>1,000-liters) ones equipped with modest and cheap skimmer (like the super skimmer) and this revolutionary system that is sending the rest to the museum?
Since we are thinking of revolutionary concepts, here is one elaborated by Christophe Soler: instead of setting up a conventional calcium reactor after the sulfur denitrator, take a kalk-reactor filled, not with coral sand, but with calcium carbonate powder. Acid water flowing slowly (5 l/h for a 500-liters tank) will dissolve easily this powder that is offering a much greater contact surface than sand. The produced calcium level should be equally greater. The internal mixing of the reactor will prevent the formation of mud. To be tested! Anyone?
MARS © Copyright 1998 - All Rights Reserved
More?
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Belgian Anthias
New member
Thiobacilllus denitrificans function well in aerobic and anaerobic conditions.
I don't disagree, but since you mention it a lot, do you have evidence that this is the primary species that grows on a reef tank sulfur denitrator?[/QUOTE]
They are probably not always the primary species in the reactor, but at my knowledge they are the only common autotropic NO3 reducing bacteria with an optimum working temp between 25°C and 30°C and PH range between 6 and 8. All others need optimum temps above 30°C, a narrow PH range of 7 or work only in very acidic conditions. It is evident that when nitrate has to be reduced in an aquarium of 27°C they have the best cards to play.
CHEMISTRY AND THE AQUARIUM by RANDY HOLMES-FARLEY: maybe you find the correct information in some articles of this author because I am not a chemist, only a hobbyist with some interests in how things work.
For me it is not important what kind of bacteria do the job as long as it is done. More important is the correct use and management of the reactor which should be easy. Only when high nitrate levels have to be removed extra attention must be made to the buffering of the water because in low PH conditions partial big water changes may be considered to solve the situation which may be the cause of possible problems. Most of the aquarists who have had problems will point to the sulphur reactor when it was the waterchange and bad management that caused the problem.
I don't disagree, but since you mention it a lot, do you have evidence that this is the primary species that grows on a reef tank sulfur denitrator?[/QUOTE]
They are probably not always the primary species in the reactor, but at my knowledge they are the only common autotropic NO3 reducing bacteria with an optimum working temp between 25°C and 30°C and PH range between 6 and 8. All others need optimum temps above 30°C, a narrow PH range of 7 or work only in very acidic conditions. It is evident that when nitrate has to be reduced in an aquarium of 27°C they have the best cards to play.
CHEMISTRY AND THE AQUARIUM by RANDY HOLMES-FARLEY: maybe you find the correct information in some articles of this author because I am not a chemist, only a hobbyist with some interests in how things work.
For me it is not important what kind of bacteria do the job as long as it is done. More important is the correct use and management of the reactor which should be easy. Only when high nitrate levels have to be removed extra attention must be made to the buffering of the water because in low PH conditions partial big water changes may be considered to solve the situation which may be the cause of possible problems. Most of the aquarists who have had problems will point to the sulphur reactor when it was the waterchange and bad management that caused the problem.
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Will become your problem some day.
No, not always.. I've done it for 15 years. At the moment, I even move caulerpa racemosa from the refugium to the main tank to feed fish.
VODKA, it works but don't say you where not warned.
Uh, OK, I won't blame you. :lol:
I've also use organic carbon for years.
No, not always.. I've done it for 15 years. At the moment, I even move caulerpa racemosa from the refugium to the main tank to feed fish.
VODKA, it works but don't say you where not warned.
Uh, OK, I won't blame you. :lol:
I've also use organic carbon for years.
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Belgian Anthias
New member
Of coarse you make it as small as you want! But it will not be able to remove the nitrate when nitrate is building up. When a to small reactor is used you will not be able to reduce the flow and not enough media and room will be available for the bacteria needed. A good reactor will have a flow between 4l/h and 10l/h for a 200l aquarium. This is easily manageable. it's a guideline. But it is with the flow the active bacteria can be managed, not with the amount of sulphur. And with a small reactor balance may not be found.
IMO, one of the significant drawbacks of sulfur denitrator is the depletion of alkalinity. Yes, one can compensate for that by adding extra aklalinity, but for those of us trying to use balanced calcium and alkalinity additive systems, such a depletion messes up that balance and requires more monitoring of calcium and alkalinity than might otherwise be needed.
Passing the water over aragonite may help boost the alkalinity, but it also boosts calcium, so at best, it just swaps a depletion of alkalinity for a steady boosting of calcium.
Of coarse you make it as small as you want! But it will not be able to remove the nitrate when nitrate is building up.
That obviously depends on the rate of feeding, and what other nitrate reduction methods are in place. I prefer to use many nutrient export method at the same time, rather than have to rely on one to carry the full load. That is especially important as almost all of these methods export some N and P, but not likely the exact ratio present in the tank. So having multiple methods allows one to pick up the slack of the others.
Passing the water over aragonite may help boost the alkalinity, but it also boosts calcium, so at best, it just swaps a depletion of alkalinity for a steady boosting of calcium.
Of coarse you make it as small as you want! But it will not be able to remove the nitrate when nitrate is building up.
That obviously depends on the rate of feeding, and what other nitrate reduction methods are in place. I prefer to use many nutrient export method at the same time, rather than have to rely on one to carry the full load. That is especially important as almost all of these methods export some N and P, but not likely the exact ratio present in the tank. So having multiple methods allows one to pick up the slack of the others.
Sulpur-denitrators where lab tested and used in public aquaria for a long time. Everything about the working is known.
Perhaps I missed it, but I didn't see a single thing that you linked to or posted that showed any evidence that Thiobacilllus denitrificans is the bacteria that grows in reef tank sulfur denitrators. Did I miss it, or are you just assuming that because it is known in environments like soil that it must be the species growing in denitrators?
Perhaps I missed it, but I didn't see a single thing that you linked to or posted that showed any evidence that Thiobacilllus denitrificans is the bacteria that grows in reef tank sulfur denitrators. Did I miss it, or are you just assuming that because it is known in environments like soil that it must be the species growing in denitrators?
Sorry, I missed the last post where you indicated that it might be other species.
One other thing of interest I found there was this comment:
"CHEMISTRY AND THE AQUARIUM by RANDY HOLMES-FARLEY: maybe you find the correct information in some articles of this author because I am not a chemist, only a hobbyist with some interests in how things work."
Thanks for the suggestion. I'm very familiar with my own articles.
One other thing of interest I found there was this comment:
"CHEMISTRY AND THE AQUARIUM by RANDY HOLMES-FARLEY: maybe you find the correct information in some articles of this author because I am not a chemist, only a hobbyist with some interests in how things work."
Thanks for the suggestion. I'm very familiar with my own articles.
No I don't think so. More flow = more oxygen= less anaerobic nitrate reduction, With the same amount of sulfur all you get is the oxidation of sufur to sufate and the creation of organic materials. When the nitrate input from the tank drops significantly , downsizing makes sense by reducing the sulfur and manipualting the flow to obtain an amount of anaerobic denitrifcation balanced to nitrate input.
BTW, one of the articles you cited actually notes the amount of sulfur to be used relates to the nitrate concentration in the aquarium.
I don't think I have a "wrong way of thinking " as you have asserted in several posts. It's obviously different than yours but I don't think it's "wrong".
I also don't think everything about sulfur denitrators is known as you assert. Can you tell me which if any heterotrophic elemental sulfur bacteria are in play if any for example? There are lot's of questions about sulfur bacteria and by extension lot's of unknowns about what is actually a happening in a sulfur reactor.
As for alternative methods for managing nitrate such as refugia, organic carbon dosing ,skimming , GAC , cryptic refugia; they are tried, safe and very useful IME and should not be set aside based on simplistic assumptions about them. A sulfur denitrator is not better or necessarily worse ;it's another tool.
I think a sulfur denitrator is a particularly very useful tool for bringing nitrates down in a short time,IME. It's usefullnes long term in maintaining a very low nitrate level is less so and more difficult with a greater potential downside.
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Belgian Anthias
New member
Ok , I try again. In a 1% reactor there is enough media to remove the nitrate produced in a well overcrowded aquarium system.. By bringing in more or less flow you bring in more or less nitrate and oxygen. In the reactor only a part is used for de-nitration By bringing in more or less oxygen and nitrate the population and the way the bacteria get their oxygen changes. In an aquarium with low nitrate levels only a small part of the reactor will be used for de-nitration purposes. When nitrate raises, which means the reactor is not able to remove it, decreasing the flow ( which is high at that moment) will lower the amount of nitrate entered and will give more space for the de-nitration process by lowering the available free oxygen. This way the bacteria will find their balance. We do this with small corrections at once.
If the reactor holds only a small amount of sulphur, based on the small amount of nitrate in the aquarium you will never be able to cope with a building up of nitrate ( which means your reactor is not big enough because he can not remove the produced nitrate any more)) When you try to , and reduce the flow, you will create the risk for anoxic conditions, and there will be not enough room. Because by reducing the flow you also reduce the nitrate available which holds the oxygen they used for de-nitration and as the reactor was already functioning at maximum capacity, all available oxygen will be depleted and as result most bacteria will die.
It is not as simple as that but that will be the result. When the reactor is big enough these problems will never occur!
In your way of thinking you would increase the flow when nitrate builds up (and decrease the flow when nitrate is lowering) which means you enter more free oxygen with the result that less de-nitration will take place. So the nitrate will build up more and the conclusion will be made that the reactor do not function!
When using Sulphur de-nitration and the basic rules are followed there will never be problems with managing the nitrate in the aquarium and the system will work without problems for years!
You will never have to consider how to protect your system from sulfide!
And all methods for removing nitrates have their cons and for but the main question we must ask is: why do we need one?
I am Dutch speaking , I am not a chemist, and I explained it in English the best way I could.
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