New sulfur denitrator working great!

[Jon_W79]

From the post below, and other posts of his, I think that @Randy Holmes-Farley believes that being very concerned about hydrogen sulfide and sulfur denitrators is not justifiable. I agree with him if that's what he believes.

The thread is called "can a sulfur denitrator be dangerous?"

 

[robbyg]

As you noticed, slowing the effluent will just generate hydrogen sulfide as the bacteria resort to using sulfate instead of nitrate.

When these reactors get nitrate down to low levels, reducing the quantity of sulfur media to tune it to your nitrate generation can help to avoid the situation you were experiencing.

Also running the effluent through GFO will help to remove hydrogen sulfide by converting it back into elemental sulfur.

I don't run one currently, but did in the past.

Dennis

Dennis I was pretty certain that reducing the effluent rate would only make problems worst but I figured why not give it a try. I was so sure that it was going to make things worst that I actually monitored it for about 3 hours and sure enough I started to smell that hydrogen sulfide odor.
If I had left it overnight I am pretty sure my tank would have crashed and the fact that this can happen was one of the reasons why I decided not to even bother removing media. My Nitrate was near zero so even half the amount of media would still be a problem.

SD reactors have there place in the hobby but if your going down the path of trying to create balance I personally feel that you have to know when it's time to move to less aggressive means of removing Nitrate. IMHO balance is not really possible if your trying to keep more fish than you should for the tank size, but in those cases keeping a SD reactor going long term is a very good solution.

If you are striving for a balanced approach of coral and fish and get to a good spot and then removing the reactor it's not a waste but more of a natural progression as you can repurpose it into a calcium reactor. That is something I will explore later down as my calcium needs increase but for now two part does the job and I have not yet reached the point of needing so much of it that the expense is killing me.

 

[robbyg]

From the post below, and other posts of his, I think that @Randy Holmes-Farley believes that being very concerned about hydrogen sulfide and sulfur denitrators is not justifiable. I agree with him if that's what he believes.

The thread is called "can a sulfur denitrator be dangerous?"

What was Randy's reason for not liking them, was it the Alk consumption? I forget.

 

[Jon_W79]

What was Randy's reason for not liking them, was it the Alk consumption? I forget.

One of the reasons is Alk consumption.

 

[Belgian Anthias]

I am in no way trying to discourage others from using a reactor as they really do an excellent job of removing Nitrate and are probably one of the fastest ways of removing Nitrate. The problem that I once again faced was that when my Nitrate started to bottom out the reactor started to dump stuff back into the water. I suspect it was hydrogen sulfide but I have no way of testing that. There was no smell of rotten eggs and nothing happened fast but I did notice that the fish were definetly having problems and two of my Tangs died with what looked like some kind of mucous deficiency or drying and irritation on their skin. I noticed all the fish rubbing themselves on the rocks and slight fin deteration. No new fish had been added to the tank for months and it was not ich or velvet nor any other kind of problem I have seen before. It also had no effect on crabs or shrimp but it did cause some stress on my SPS corals.

It happens using anoxic kept denitrators and is created by the way the reactor is managed. When the nitrate level descends at the same flow less nitrate is entered. Keeping the same flow to keep the reactor anoxic will starve the bacteria needing nitrate by which anaerobic remineralization takes place reducing sulfate to HS. Autotrophic Bacteria normally using up produced HS in anoxic conditions need nitrate. ( the same bacteria able to reduce nitrate using elemental sulfur)
Correct flow management is important using BADES. If the flow is managed in the function of keeping the reactor anoxic instead of the function of the nitrate content then it may go wrong the way you describe. In many cases, reactors used are too small for using BADES and for keeping a steady low nitrate level while having a high daily nitrate production. One can not remove what is not entered. A normal BADES reactor has a flow of at least 1x the total system volume daily and a capacity of 2X the system volume daily. Such a reactor must be big enough as part of the reactor must be available for aerobic remineralization to use up the increasing amount of oxygen entered following the increasing flowrate, which means it is partially used as an effective remineralization filter.

Exporting safely stored nitrogen does not solve a thing as long there is nothing done to correct the source, why nitrate is able to build up a reserve.

Exporting only nitrate is done to restore the nutrient balance.
Denitrification does NOT support the carrying capacity.
An algae filter has a completely different purpose, it will not restore the nutrient balance but will support the carrying capacity.
An algae filter can be used for restoring the nutrient balance using AAM, active algae management.

 

[Belgian Anthias]

What was Randy's reason for not liking them, was it the Alk consumption? I forget.

In a BADESS the bacteria grow on a sulfur/ calcium carbonate substrate. The carbonate needed is retrieved from the substrate which means system alkalinity is NOT used.
In some cases, alkalinity is supported.
55S + 44CaCO 3 + 50NO 3- + 18H2O + 4NH4+ → 4 C5H7O2N + 25N 2 + 55SO4 2- + 44Ca 2+ + 24HCO3- (TC ZHANG 2004) ref: MB CMF De Haes 2017

Using BADES without providing a calcium-carbonate based substrate will consume system alkalinity. This should not be considered a problem as most reef tanks consume alkalinity, without BADES. It must be corrected anyway.

 

[Randy Holmes-Farley]

In a BADESS the bacteria grow on a sulfur/ calcium carbonate substrate. The carbonate needed is retrieved from the substrate which means system alkalinity is NOT used.
In some cases, alkalinity is supported.
55S + 44CaCO 3 + 50NO 3- + 18H2O + 4NH4+ → 4 C5H7O2N + 25N 2 + 55SO4 2- + 44Ca 2+ + 24HCO3- (TC ZHANG 2004) ref: MB CMF De Haes 2017

Using BADES without providing a calcium-carbonate based substrate will consume system alkalinity. This should not be considered a problem as most reef tanks consume alkalinity, without BADES. It must be corrected anyway.

Alkalinity is ALWAYS consumed by the bacterial process.

One can choose to fully or partly offset that alk loss in various ways, including as you suggest, dissolving calcium carbonate.

That method, sadly, will constantly boost calcium (whether needed or not).

IMO, folks might be better off just adding more alkalinity as needed, rather than that calcium carbonate process, but one could also dose less calcium if one chooses to use the calcium carbonate dissolution for some reason.

 

[Jon_W79]

I think that for a sulfur denitrator to produce hydrogen sulfide would require organic matter. I guess that if a sulfur denitrator is dirty on the inside it could produce hydrogen sulfide. A good pre-filter could help prevent that( I have my feed pump in a big filter sock).

 

[Belgian Anthias]

Everything has a reason!

There is a very good reason for adding calcium carbonate as a substrate using a BADES reactor and that reason is NOT the main system alkalinity.

In a BADES bio-reactor also aerobic remineralization takes place, including nitrification; ( producing acids)

In a sulfur denitrator which is kept anoxic and nitrate levels decrease and nitrate becomes limited available, mainly HS will be used by the autotrophs, HS produced by heterotrophs reducing sulfate. If alkalinity is always consumed by the bacterial process, which process? HS will be reduced partially or completely, depending on the nitrate/HS ratio, producing sulfur or and sulfate, having a different effect on the local alkalinity. In a denitrifying biofilm growing on elemental sulfur pH and alkalinity is an important factor for bacterial growth, and not only for those bacteria using elemental sulfur. High local acidity will have an influence on bacterial growth and the kind of bacteria which may grow. We do not want those bacteria thriving in an acidic environment replacing the bacteria needed.
Alkalinity is ALWAYS consumed by autotrophic bacterial processes, producing acids. Then the accids may be used to dissolve calcium carbonate preventing the pH to drop to low. Not in the aquarium system, but in the reactor, there where the action is. The bacteria can only use what is present in the reactor, there where all the different reactions take place. That is why some calcium carbonate is added to the reactor. A BADES reactor will not work without all the other essential bacteria. Saying a sulfur denitrator always consumes alkalinity is NOT correct.


What we have to know for managing the system is what the end result will be, and how to make corrections if needed.
What is coming out of the reactor?
Using a refugium makes it possible to make corrections before the water is added to the main system. This is good advice for any filtration method.

Using an anoxic kept sulfur denitrator for lowering a high to very high nitrate level without adding calcium carbonate is not a good idea at all due to the high acid production. Using an anoxic kept denitrator is never a good idea.

For making use of the BADES process anoxic conditions are NOT needed.

 

[Randy Holmes-Farley]

If alkalinity is always consumed by the bacterial process, which process?

....
For making use of the BADES process anoxic conditions are NOT needed.

Conversion of sulfur to sulfate consumes alkalinity, no matter how you do it. it has nothing to do with being anoxic.


Here is the balanced reaction that produces N2 that applies regardless of anything else you add to the mix:

2 H2O + 5 S + 6 NO3– → 3 N2 + 5 SO42- + 4 H+

 

[Randy Holmes-Farley]

In a BADESS the bacteria grow on a sulfur/ calcium carbonate substrate. The carbonate needed is retrieved from the substrate which means system alkalinity is NOT used.
In some cases, alkalinity is supported.
55S + 44CaCO 3 + 50NO 3- + 18H2O + 4NH4+ → 4 C5H7O2N + 25N 2 + 55SO4 2- + 44Ca 2+ + 24HCO3- (TC ZHANG 2004) ref: MB CMF De Haes 2017

Using BADES without providing a calcium-carbonate based substrate will consume system alkalinity. This should not be considered a problem as most reef tanks consume alkalinity, without BADES. It must be corrected anyway.

This reaction is the whole problem!!!!! BADES should be renamed BAD. lol

You took an alkalinity depleting process, dissolved a bunch of calcium carbonate to make up for the alkalinity depletion, and made it into a massive calcium doser, without a balanced amount of alkalinity.

That reaction adds 44 moles of calcium and only 24 moles of alkalinity. A balanced amount of alkalinity would be 88 moles.

BADES took an alk problem and made it into a calcium problem.

Is that desirable?

 

[Belgian Anthias]

I think that for a sulfur denitrator to produce hydrogen sulfide would require organic matter. I guess that if a sulfur denitrator is dirty on the inside it could produce hydrogen sulfide. A good pre-filter could help prevent that( I have my feed pump in a big filter sock).

It will not prevent HS production in the reactor.

Often such denitrators operate at a drip rate and removing TOC may help for preventing clogging and a relative high HS production. Due to the low flow rate, HS overproduction is not a high-risk factor for the tank, but the filter may turn into an HS factory instead of a denitrator, if not managed correctly.
Removing biowaste from the influent should be basic management when using an anoxic kept sulfur denitrator.

 

[Jon_W79]

It will not prevent HS production in the reactor.

Often such denitrators operate at a drip rate and removing TOC may help for preventing clogging and a relative high HS production. Due to the low flow rate, HS overproduction is not a high-risk factor for the tank, but the filter may turn into an HS factory instead of a denitrator, if not managed correctly.
Removing biowaste from the influent should be basic management when using an anoxic kept sulfur denitrator.

I believe that organic matter is required for the production of hydrogen sulfide. Are dead bacteria "organic matter"? If dead bacteria are not "organic matter", I believe what I said is correct.

The risks of H2S are far higher in a carbon denitrator than a sulfur denitrator (IMO).

I'm not sure there's a process whereby low flow results in the sulfur being converted into hydrogen sulfide, but the reaction of organic matter with sulfate in low O2 seawater by bacteria does result in hydrogen sulfide, and any tank water that gets stagnant has organics and sulfate in it, and can make hydrogen sulfide. A carbon denitrator has extra organic matter added, and hence is functioning at the edge of consuming the nitrate, but not consuming the sulfate.

 

[Belgian Anthias]

This reaction is the whole problem!!!!! BADES should be renamed BAD. lol

You took an alkalinity depleting process, dissolved a bunch of calcium carbonate to make up for the alkalinity depletion, and made it into a massive calcium doser, without a balanced amount of alkalinity.

That reaction adds 44 moles of calcium and only 24 moles of alkalinity. A balanced amount of alkalinity would be 88 moles.

BADES took an alk problem and made it into a calcium problem.

Is that desirable?

I took nothing! Nature does it for us. It is the end result that counts, not a single process. But to have an idea of what will be the end result one must have an idea of the different processes taking place.

BADES is an acronym for Biological Anaerobic Denitrification using Elemental Sulfur, a natural process taking place everywhere in the tank. What BAD should stand for?

A sulfur denitrator or a BADES system does NOT ALWAYS deplete system alkalinity.

Sulfate reduction in combination with the oxidation of reduced sulfur compounds will cause an overall increase in alkalinity as illustrated by the reduction of sulfate to sulfide and subsequent re-oxidation to sulfate VanRijn2005)
SO4 2- + 10H+ + 8e- ⇒ H2 S + 4H2 O
( (Alkalinity gain= 2 meq alkalinity per mole SO4 2- of 100 mg CaCO3 /mole SO4 2- )
5H2 S + 8NO3 - = + 5SO4 2- + 4N2 + 4H2 O + 2H+
(Alkalinity consumption = 2 meq per 5 moles H2 S of 20 mg CaCO3 /mole H2 S) VanRijn2005)
As with heterotrophic denitrification, the combined autotrophic denitrification by means of sulfur derivatives, the reduction of sulfate to sulfide, the oxidation of sulfide and the reduction of nitrate has the same positive effect on the alkalinity by increasing it with 3.57mg CaCO3. (VanRijn2005)
ref: MB CMF de Haes 2017-2019
If nitrate is limited available ( often the case in an anoxic kept sulfur denitrator once the nitrate level is descending due to the limited flow) a lot of HS may be produced and HS reduction may become partial depending on the HS/nitrate ratio there where the action is, producing S which only anaerobically can be used when HS or other sulfur compounds availability is insufficient, the BADES process. All these processes also take place in a normal nitrifying biofilm and everywhere in the tank.

It all depends on how a denitrifying filter is managed. Without adding elemental sulfur BADES will take place, although very limited. The bacteria responsible for BADES are always present everywhere as they make use of constantly produced HS, aerobically using oxygen and anaerobically exporting nitrate. A normal aerobic remineralization filter has a certain denitrification capacity, which can be influenced by managing elemental sulfur availability.

If nitrate becomes limited available most denitrification taking place will be autotrophic and by using HS, not S

So, the reaction you consider a problem does NOT represent the whole picture, it is only a small part of what really happens. and which may take place everywhere a calcium carbonate substrate is available, in the entire tank.

Yes , I consider calcium production desirable because most reefers have to add calcium.

Using BADES, calcium production can be managed and depends on the amount of nitrate exported by BADES which is manageable as desired. If too much calcium is produced the production rate can be controlled. Normal use, the calcium production will be insufficient for replacing the consumption.
One can use two reactors, one containing sulfur, the other containing shell grit. See MAAO.
I prefer to use a mixed substrate because the processes producing acids can take place where the substrate needed is made available.

To lower the nitrate level only a little more as the daily nitrate overproduction must be removed daily, which means a good BADES System should be able to remove +- 2ppm Nitrate daily, more should be planned for a high nutrition system.

Using an anoxic sulfur denitrator, a minimal daily flow of the total tank volume is needed to keep the nitrate level at +-2ppm ( having 2ppm overproduction daily) This when 0 nitrates in the effluent are targetted, which I do not recommend using BADES.

According to the Zhang formula, approximately 1.76mg Ca is produced per 3.1mg NO3. If 10 ppm nitrate is removed per week and is removed by BADES, MAX 5.68 ppm calcium can be added on a weekly basis. According to your own calculation, only MAX 4.3 ppm of calcium may be added. (HolmesFarley 2003) The formula of Zhang takes into account the bacterial growth needed and is closer to reality. In practice, the calcium production will be a lot less.

In a reef tank, calcium and carbonate are NOT consumed in balance . There ALWAYS will be an imbalance.

Remineralization including nitrification and denitrification takes place everywhere in the tank. Depending on the substrate there where the processes take place, alkalinity will be consumed or calcium produced. A reef tank is filled up with calcium carbonate and acids are produced everywhere, dissolving substrate. Also, the consumers of calcium do not all consume carbonate or bicarbonate from the surrounding water, some calcareous algae produce calcium carbonate internally using Ca and CO2. For a lot of marine algae, internal calcification is a survival strategy, for fast retrieving available CO2 as it is limited available in seawater. The calcification rates of corals, which take place on the outside, are mainly driven by CO3 availability, if there where the action is calcium availability is not limited.

Also, Gypsum may be produced, etc... etc.....

For these reasons, a CO2-driven calcium reactor does increase the unbalance because the total consumption and production of calcium and or carbonate are NOT in the balance of CaCO3. We do have to manage the calcium content anyway. Such a CO2-driven calcium reactor does include a much greater risk than a BADES system ever can produce.

Instead of exporting nitrate using BADES one is able to stop the production of nitrate by eliminating the installed nitrification capacity by adding carbohydrates, messing up the entire natural balance in the tank. Also, these processes may consume alkalinity which must be managed and it has been shown to harm, even kill corals. (ref: MB vodka dosing. CMF De HAES 2017 ) The export rate depends on a skimmer and is unknown but has been shown to be max +- 35%. The risks, the many side effects, and possible problems caused by human error are much higher compared to using a BADES System for exporting nitrate. Using BADES the nitrate export rate is known and can easily be managed as desired, without removing from the naturally installed carrying capacity present in the system.

Using a denitrator, it is the intention to only export nitrate, leaving other building materials and nutrients behind.
it may have a lot more side effects than only calcium production. For exporting nitrogen and other nutrients and building materials I prefer to make use of Active Algae Management, AAM, cultivating algae in a refuge, and maintaining the desired minimal carrying capacity by active feeding. To export nitrogen one has to harvest.
BADES may be the best solution available if it is the intention ONLY to export safely stored nitrogen considered not needed. To fix the N/P ratio also AAM can be used.

In practice the calcium production will be a lot less as part of the denitrification will be heterotrophic and or autotrophic using HS instead of S, processes removing nitrate and boosting alkalinity if HS is produced by the reduction of sulfate.

BADES can also be used to increase the natural denitrification capacity of a normal nitrifying remineralization biofilm.

I do not see how calcium production of a correct managed BADES System may become a problem in a reef aquarium, a problem that is not taken care of by normal system management.

Why BADES is BAD? Compared to? For exporting safely stored nitrogen, Nitrate!!!

Does the cure include higher risks compared to the risks represented by the nitrate reserve? Which are?


One must be aware only exporting nitrate does not solve a nutrient problem. For this one has to correct the source, why usable nitrate can build up slowly in a well-lit aquarium? In most cases, increasing nutrient reserves are the messengers, the results of an existing problem, not the cause.

 

[Randy Holmes-Farley]

I took nothing! Nature does it for us. It is the end result that counts, not a single process. But to have an idea of what will be the end result one must have an idea of the different processes taking place.

BADES is an acronym for Biological Anaerobic Denitrification using Elemental Sulfur, a natural process taking place everywhere in the tank. What BAD should stand for?

A sulfur denitrator or a BADES system does NOT ALWAYS deplete system alkalinity.

Sulfate reduction in combination with the oxidation of reduced sulfur compounds will cause an overall increase in alkalinity as illustrated by the reduction of sulfate to sulfide and subsequent re-oxidation to sulfate VanRijn2005)
SO4 2- + 10H+ + 8e- ⇒ H2 S + 4H2 O
( (Alkalinity gain= 2 meq alkalinity per mole SO4 2- of 100 mg CaCO3 /mole SO4 2- )
5H2 S + 8NO3 - = + 5SO4 2- + 4N2 + 4H2 O + 2H+
(Alkalinity consumption = 2 meq per 5 moles H2 S of 20 mg CaCO3 /mole H2 S) VanRijn2005)
As with heterotrophic denitrification, the combined autotrophic denitrification by means of sulfur derivatives, the reduction of sulfate to sulfide, the oxidation of sulfide and the reduction of nitrate has the same positive effect on the alkalinity by increasing it with 3.57mg CaCO3. (VanRijn2005)
ref: MB CMF de Haes 2017-2019
If nitrate is limited available ( often the case in an anoxic kept sulfur denitrator once the nitrate level is descending due to the limited flow) a lot of HS may be produced and HS reduction may become partial depending on the HS/nitrate ratio there where the action is, producing S which only anaerobically can be used when HS or other sulfur compounds availability is insufficient, the BADES process. All these processes also take place in a normal nitrifying biofilm and everywhere in the tank.

It all depends on how a denitrifying filter is managed. Without adding elemental sulfur BADES will take place, although very limited. The bacteria responsible for BADES are always present everywhere as they make use of constantly produced HS, aerobically using oxygen and anaerobically exporting nitrate. A normal aerobic remineralization filter has a certain denitrification capacity, which can be influenced by managing elemental sulfur availability.

If nitrate becomes limited available most denitrification taking place will be autotrophic and by using HS, not S

So, the reaction you consider a problem does NOT represent the whole picture, it is only a small part of what really happens. and which may take place everywhere a calcium carbonate substrate is available, in the entire tank.

Yes , I consider calcium production desirable because most reefers have to add calcium.

Using BADES, calcium production can be managed and depends on the amount of nitrate exported by BADES which is manageable as desired. If too much calcium is produced the production rate can be controlled. Normal use, the calcium production will be insufficient for replacing the consumption.
One can use two reactors, one containing sulfur, the other containing shell grit. See MAAO.
I prefer to use a mixed substrate because the processes producing acids can take place where the substrate needed is made available.

To lower the nitrate level only a little more as the daily nitrate overproduction must be removed daily, which means a good BADES System should be able to remove +- 2ppm Nitrate daily, more should be planned for a high nutrition system.

Using an anoxic sulfur denitrator, a minimal daily flow of the total tank volume is needed to keep the nitrate level at +-2ppm ( having 2ppm overproduction daily) This when 0 nitrates in the effluent are targetted, which I do not recommend using BADES.

According to the Zhang formula, approximately 1.76mg Ca is produced per 3.1mg NO3. If 10 ppm nitrate is removed per week and is removed by BADES, MAX 5.68 ppm calcium can be added on a weekly basis. According to your own calculation, only MAX 4.3 ppm of calcium may be added. (HolmesFarley 2003) The formula of Zhang takes into account the bacterial growth needed and is closer to reality. In practice, the calcium production will be a lot less.

In a reef tank, calcium and carbonate are NOT consumed in balance . There ALWAYS will be an imbalance.

Remineralization including nitrification and denitrification takes place everywhere in the tank. Depending on the substrate there where the processes take place, alkalinity will be consumed or calcium produced. A reef tank is filled up with calcium carbonate and acids are produced everywhere, dissolving substrate. Also, the consumers of calcium do not all consume carbonate or bicarbonate from the surrounding water, some calcareous algae produce calcium carbonate internally using Ca and CO2. For a lot of marine algae, internal calcification is a survival strategy, for fast retrieving available CO2 as it is limited available in seawater. The calcification rates of corals, which take place on the outside, are mainly driven by CO3 availability, if there where the action is calcium availability is not limited.

Also, Gypsum may be produced, etc... etc.....

For these reasons, a CO2-driven calcium reactor does increase the unbalance because the total consumption and production of calcium and or carbonate are NOT in the balance of CaCO3. We do have to manage the calcium content anyway. Such a CO2-driven calcium reactor does include a much greater risk than a BADES system ever can produce.

Instead of exporting nitrate using BADES one is able to stop the production of nitrate by eliminating the installed nitrification capacity by adding carbohydrates, messing up the entire natural balance in the tank. Also, these processes may consume alkalinity which must be managed and it has been shown to harm, even kill corals. (ref: MB vodka dosing. CMF De HAES 2017 ) The export rate depends on a skimmer and is unknown but has been shown to be max +- 35%. The risks, the many side effects, and possible problems caused by human error are much higher compared to using a BADES System for exporting nitrate. Using BADES the nitrate export rate is known and can easily be managed as desired, without removing from the naturally installed carrying capacity present in the system.

Using a denitrator, it is the intention to only export nitrate, leaving other building materials and nutrients behind.
it may have a lot more side effects than only calcium production. For exporting nitrogen and other nutrients and building materials I prefer to make use of Active Algae Management, AAM, cultivating algae in a refuge, and maintaining the desired minimal carrying capacity by active feeding. To export nitrogen one has to harvest.
BADES may be the best solution available if it is the intention ONLY to export safely stored nitrogen considered not needed. To fix the N/P ratio also AAM can be used.

In practice the calcium production will be a lot less as part of the denitrification will be heterotrophic and or autotrophic using HS instead of S, processes removing nitrate and boosting alkalinity if HS is produced by the reduction of sulfate.

BADES can also be used to increase the natural denitrification capacity of a normal nitrifying remineralization biofilm.

I do not see how calcium production of a correct managed BADES System may become a problem in a reef aquarium, a problem that is not taken care of by normal system management.

Why BADES is BAD? Compared to? For exporting safely stored nitrogen, Nitrate!!!

Does the cure include higher risks compared to the risks represented by the nitrate reserve? Which are?


One must be aware only exporting nitrate does not solve a nutrient problem. For this one has to correct the source, why usable nitrate can build up slowly in a well-lit aquarium? In most cases, increasing nutrient reserves are the messengers, the results of an existing problem, not the cause.

There is no getting around the fact that the process depletes alkalinity, and if you add on dissolution of calcium carbonate to mitigate that alk drop, calcium rises.

Gypsum is soluble in seawater.

 

[Belgian Anthias]

There is no getting around the fact that the process depletes alkalinity, and if you add on dissolution of calcium carbonate to mitigate that alk drop, calcium rises.

Gypsum is soluble in seawater..

Gypsum is found in SLAD systems, making use of BADES for cleaning groundwater for consumption. ( Zhang 2004)
Making use of the MAAO method, using separate reactors, it was shown produced sulfate precipitates in the calcium reactors and is removed replacing the substrate. This limits calcium and sulfate production if it is gypsum, which was not determined? In such calcium reactors, the influent may have a pH far below 7 pH, depending on the nitrate removal rate in the BADES reactors.

Calcium production is NOT considered a problem and certainly does not increase the risk factors for removing safely stored nitrogen.

A BADESS does NOT consume system alkalinity and produces some calcium, only if that is the choice of the user.

 

[Belgian Anthias]

Exporting nitrate using BADES in an anoxic reactor means that alkalinity consumed due to nitrate production is not compensated for. Adding calcium carbonate as substrate only compensates for the autotrophic denitrification processes using elemental sulfur and or HS and other sulfur compounds.
Normally nitrification processes are compensated for when nitrate is used by photo-autotrophs, algae, phytoplankton, and heterotrophic anaerobic remineralization taking place in most biofilms. Heterotrophic bacteria prefer ammonium as a nitrogen source for growth.

Nitrification processes taking place on a substrate of calcium carbonate will not consume system alkalinity and must not be compensated for. Using up the nitrate will increase alK. Calcium is produced. A reef aquarium does contain a lot of calcium carbonate substrate which is often bio-fouled.

Using BADES in a remineralization filter using a mixed substrate sulfur/calcium carbonate the acids produced by both nitrification and autotrophic denitrification may be neutralized, increasing the calcium production of the filter.

For the moment my preferred nutrient management method is AAM, Active Aquarium Management, which combines an effective remineralization filter to keep TOC and DOC very low, followed by an algae filter using up most produced nitrate and phosphate. The big difference compared to normal management is that the desired minimal carrying capacity is maintained by actively feeding the algae maintaining the growth rate needed to support the carrying capacity at all times. This way the nutrient content can be managed as desired, the nutrient balance easily restored, by using for the target nutrient(s)-modified feed.
The use of a skimmer is not recommended, which means the main source for building up a nutrient unbalance is no longer needed. Algae can be used as food, for the tank, and on your table. MBAAM can also be used for producing bioflocs, usable as food for most reef fish and filter feeders.

 

[ReeferBud]

im glad it worked out for you.

I’ve been running my aquamaxx TS-3 for almost 4 years and it does a great job of keeping nitrates in check. It’s actually so good at reducing nitrates to zero that I dose KNO3 to keep NO3 at 3-5ppm.

The only issue I occasionally have is that the sulfur gets clogged or compacted and water doesn’t circulate effectivelly, and the pump pressure actually actually lifts the entire sulfur/calcium carbonate media off the bottom of the chamber. I then have to open the reactor to wash the media, which restarts the bacteria colonization process and send my tank into a bit of a nitrate roller coaster for a few weeks, which noticeably impacts the corals’ health.

The issue I described having with the SD is happening at the moment.

After about 6 months, I start to notice the formation of a form of mulm in the reactor and it starts to coat and eventually bind and clump the sulfur beads together. When this happens, the water no longer flows through the sulfur beads and the pressure of the circulating pump “lifts” the entire sulfur and calcium carbonate media off the bottom plate of the reactor, as shown in the picture.

This forces me to open the reactor and wash the sulfur media, killing the bacteria in the process and restarting the colonization process in the reactor from scratch (just in case, there’s way too much mulm to rinse with aquarium water and requires a lot of water to rinse). In the past, I have noticed the corals don’t like this.

Has anyone experienced this or have any thoughts as to how to prevent this from happening?

 

[Jon_W79]

The issue I described having with the SD is happening at the moment.

After about 6 months, I start to notice the formation of a form of mulm in the reactor and it starts to coat and eventually bind and clump the sulfur beads together. When this happens, the water no longer flows through the sulfur beads and the pressure of the circulating pump “lifts” the entire sulfur and calcium carbonate media off the bottom plate of the reactor, as shown in the picture.

This forces me to open the reactor and wash the sulfur media, killing the bacteria in the process and restarting the colonization process in the reactor from scratch (just in case, there’s way too much mulm to rinse with aquarium water and requires a lot of water to rinse). In the past, I have noticed the corals don’t like this.

Has anyone experienced this or have any thoughts as to how to prevent this from happening?

I'm having something similar happening to my SD(I think I may have the same sulfur). If the SD is reducing nitrate the same as before and/or the rocks aren't touching the top of the SD, I don't think the sulfur needs to be removed. If the sulfur needs to be removed, I think you can do a small water change, and put some of the old water in a bucket(and some of it in another container), put the sulfur from the SD in the bucket of water, stir it well with your hands(you could start removing cloudy water and start and keep replacing with old tank water until the water is clear, while occasionally stirring the sulfur), and then put the sulfur back in the sulfur denitrator. I think the SD can be back to working well soon if you do this.

 

[Jon_W79]

I'm having something similar happening to my SD(I think I may have the same sulfur). If the SD is reducing nitrate the same as before and/or the rocks aren't touching the top of the SD, I don't think the sulfur needs to be removed. If the sulfur needs to be removed, I think you can do a small water change, and put some of the old water in a bucket(and some of it in another container), put the sulfur from the SD in the bucket of water, stir it well with your hands(you could start removing cloudy water and start and keep replacing with old tank water until the water is clear, while occasionally stirring the sulfur), and then put the sulfur back in the sulfur denitrator. I think the SD can be back to working well soon if you do this.

I don't think it is that badly clogged if the rocks aren't touching the top of the sulfur denitrator(especially if you have excess sulfur, which means that you're running 0 nitrate in the effluent). It might could remove nitrate just as well as before even if the rocks do touch the top of the SD(but you probably need to check the nitrate level more often to decide if you need to do something about the sulfur if that happens). If you use a lot of excess sulfur, if some of it gets clogged there is probably a lot of other areas of the sulfur that enough bacteria can grow to continue to reduce nitrate by the same amount as before the sulfur got partly clogged.