Sulphur in the reefaquarium

[Randy Holmes-Farley]

About using BADES in a reef aquarium I do not think so, it is not a solution at all if given info is not close to reality.
This does not mean the provided information is incorrect, the recommendation may be not correct or and incomplete to retrieve the desired results in a present situation.

A sulfur denitrator is an ok choice if nitrate control is difficult, but somehow one has to deal with depleting alkalinity. If you choose to replace the lost alkalinity by dissolving calcium carbonate, then you have to deal with rising calcium. All these things can be readily accomplished, I'm just not convinced it is the best way due to these complexities.

 

[Belgian Anthias]

Why a sulfur denitrator has a bad reputation on reefers fora?

Two decades ago all the information for correctly using a sulfur denitrator in a closed marine aquarium system was available. Things changed are now proof can be provided for what was then only experienced in practice.

Somebody posted on a reefers forum a denitrator has the highest efficiency if DO is kept below 0.5ppm, which is correct. It is a fact anaerobic denitrification, both heterotrophic and autotrophic, has the highest efficiency below 0.5ppm DO. Since then some reefers started to use a sulphur denitrator as it was a carbon-based denitrator (heterotropic denitrification and anaerobic remineralization takes place in an anoxic environment) and try to keep the reactor anoxic to have max efficiency.
Does it help to have 100% efficiency if the same time the removal rate is insufficient due to an insufficient refresh rate due to the limited possible flow?
The influent water contains +- 6ppm DO, at a low or a high nitrate level the same amount of oxygen must be consumed to keep the reactor anoxic. About the same amount of nitrogen must be removed daily to keep the nitrate level steady. Remove 1 ppm nitrogen overproduction daily using a nitrate content of 20ppm is not that difficult using a sulfur denitrator, removing the same amount daily while keeping on a nitrate level of 2ppm the daily flow must increase with a factor X 10 entering 10X more oxygen daily which must be consumed daily if the reactor is kept anoxic. Good luck!

Wrong management based on correct but incomplete information may cause sulfate reduction in a way turning such an anoxic reactor into a H2S factory if in the reactor all nitrate is used up.
Because of incomplete but correct information, living its own life on the internet.

Longouet and Martin, the Godfathers of marine BADES Systems, never published a sulfur denitrator must be kept anoxic after startup. Martin published two decades ago such a reactor works fine at a DO of 3 ppm! ref: http://www.baharini.eu/baharini/doku.php?id=en:badess:bades:maao
Now we also know why BADES works fine at 3ppm DO, it works also in normal aquarium conditions, 6ppm DO


A BADES system is not kept anoxic, it is not necessary! ref: http://www.baharini.eu/baharini/doku.php?id=en:badess:start

 

[Belgian Anthias]

A sulfur denitrator is an ok choice if nitrate control is difficult, but somehow one has to deal with depleting alkalinity. If you choose to replace the lost alkalinity by dissolving calcium carbonate, then you have to deal with rising calcium. All these things can be readily accomplished, I'm just not convinced it is the best way due to these complexities.

My opion a sulphur reactor is a bad choice if kept anoxic. I do not advise such a reactor for to be used in a life support system.
A sulphur denitrator may be responsible for all those things.

Nitrogen control has never been difficult, using a bio-filter or refuge for active nitrogen management. The carrying capacity of the system can be adjusted as desired at all times, allowing a high bioload in a mixed reef system.
Banning the bio-filter, another thing living its own life on reefers fora of which I do not understand why?

One must deal with all those " complexities" in a reef tank anyway, certainly in a high input mixed reef tank using a skimmer.
A BADES System may produce calcium and bicarbonate and one does not have to deal with alkalinity losses due to BADES. I do not see the complexities, different from normal management.

Sulfate is produced.

A BADES system provides full control over the daily nitrate removal rate and the nitrate level for the user which makes active nitrogen management very easy in high input, high output tanks with a skimmer.

For balanced and unbalanced nutrient export I only have one better and safe option, this if the bio-load is low.

 

[purp]

Just FYI. I put in 500g of this in a filter sock in my sump. I measure alkalinity every 30 minutes. I'll keep yall posted. My nitrates are not very high atm (10 ppm), and I also have some gfo in a bag in my sump as well. Should be interesting!

No need to fight! Lets all be productive and see how this goes.

 

[purp]

Can we maybe talk about the fate of sulfate (hah!) in this type of system?

 

[Belgian Anthias]

Sulphate production:

For each ion nitrate that is reduced by chemo-autotrophic bacteria ( T.denitrificans) through oxidation of elemental sulfur, 1.1 ion sulfate is formed. Nitrate weighs 62 g / mol and sulphate 96 g / mol. In theory, 1.7 grams of sulphate are produced for every gram of nitrate that is reduced. Theoretically, therefore, + - 7.5 mg of sulphate would be produced per NO3-N reduced (N = 14.007g / mol). ref: http://www.baharini.eu/baharini/doku.php?id=nl:badess:theorie:de_neveneffecten#sulfaat

In practice, the sulphate production in a BADESS will be a lot less. A lot of other processes play a main role in the final result.

Sulphate reduction also takes place, producing HS

When Nitrate is reduced by T. denitrificans by HS, only 0.77 SO4 is produced instead of 1.1 when elemental sulfur is used.
When nitrate is reduced by green sulfur bacteria by means of HS, only 0.625 SO4 is produced in the middle layers where sufficient nitrate is present. No sulphate is produced but sulfur when nitrate consumption cannot be replenished sufficiently quickly and the nitrate/HS ratio drops to 2/5 .(CherEnCo2008) ref: http://www.baharini.eu/baharini/doku.php?id=nl:badess:theorie:de_neveneffecten#waterstofsulfide


Michel HIGNETTE, President of the Union of Conservators of Aquariums of France (UCA), finds that sulphate is precipitated in the lime columns and probably removed when these columns are cleaned and refreshed when using sulfur reactors. That would explain why in practice not much can be noticed about the sulphate production caused by the BADES process. This was established at the MAAO, National Museum of the Arts of Africa and Africa (MAAO) in Paris. When using 4 sulfur reactors with a total of 860 kg of sulfur, no increase in the sulphate content was measured until a time when lime reactors slipped tightly and the reactor water ended up directly in the aquarium water via a bypass, whereby the sulphate content in the aquarium water increased considerably.(Hignette1997)
Even with peaks of up to 5300mg of sulphate / l, no abnormal behavior of the fish was found.(Hignette2003) ref: http://www.baharini.eu/baharini/doku.php?id=en:badess:bades:maao

In the MAAO various samples were taken of used maerl and it was found that the use of a maerl ( calcium carbonate media) behind a sulfur column contains on average up to twice as much sulphate as fresh maerl and used as maerl in the aquarium. Fresh maerl contains 219 mg sulphate / gram, maerl in the aquarium 220mg / gram, maerl in the lime columns after the sulfur column an average of 421mg per gram maerl.(Hignette2001) ref: http://www.baharini.eu/baharini/doku.php?id=en:badess:bades:maao 200mg sulphate may be fixed per gram of maerl!

Fluidized bed reactors were used in a large-scale pilot project for the purification of water with elemental sulfur in an aquaculture system. Only 1/4 to 1/2 of the theoretically expected amount of sulfate production was determined. There was almost no difference between the sulfate content of supply and discharge. .(LChristiansonEnCo2015-09)

Commercial salt mixtures can deviate considerably from the amount of sulphate found in natural seawater, both upwards and downwards. Natural seawater contains 28 millimoles of sulphate / kg. In a comparative study in 1999, Coralife contained only 15 mmol sulfate / kg and SeaChem 37 mmol sulfate / kg (Atkinson Bingman 1999). When using Coralife, it will take several years for the natural seawater sulfate level to be reached and a little longer to reach SeaChem. In the meantime, the compositions of many commercial salt mixtures have changed slightly, but there are still major differences. ref: https://reefhub.pl/test-of-marine-salts/ To correct sulphate content one may make a choice of the salt used for waterchanges.

In a BADES System always calcium carbonate media is used as a carbon source and not only to prevent alkalinity consumption. In BADESSystems we do not make use of anoxic kept sulphur-denitrators!
I advise to refresh 1/2 the calcium carbonate media every 6 months.

 

[Randy Holmes-Farley]

Can we maybe talk about the fate of sulfate (hah!) in this type of system?

Sulfate is the third most abundant ion in seawater by weight, after sodium and chloride. There’s no substantial concern about adding more of it in this fashion.

 

[purp]

Not even in a long term manner by throwing off the anion balance from "normal" to sulfate heavy? There's a ton of literature on sulfur fate in the subsurface and near the water interface, but not quite as much I can find on dissolved sulfate in the water column.

 

[Randy Holmes-Farley]

FWIW, the vsriou

Not even in a long term manner by throwing off the anion balance from "normal" to sulfate heavy? There's a ton of literature on sulfur fate in the subsurface and near the water interface, but not quite as much I can find on dissolved sulfate in the water column.

The issue is not so much what sulfate does or doesn’t do, but how little you will change it (although it also doesn’t do much in an aerated water column).

It starts at 2700 ppm, so a hundred ppm plus it minus is a minor change. There are bigger impacts on the sulfate level in tanks than this. Salt mixes start with a fairly wide range of sulfate to chloride. There is little evidence the ratio is very important.

The absolute concentration varies more in the ocean by salinity changes than this small addition. Use calcium chloride and don’t add sulfate somehow, sulfate will decline. Use Epsom salts only for magnesium and sulfate will rise.

water changes will correct for sulfur denitrator addition of sulfate. Certainly, tanks doing no water changes need to worry more about all of these issues than those that do water changes. Thus is one reason I recommend going water changes: controlling those things you do not regularly measure.

 

[Belgian Anthias]

If BADES is used in combination with calcium carbonate, no alkalinity is consumed since the carbonate supplied by the lime is used as a carbon source. As a result, there is a surplus of calcium and bicarbonate. If BADES bio-reactors or BADES columns are used, also a substantial part of nitrification will not consume alkalinity, resulting in a surplus of calcium . If sufficient nitrate remains available, the alkalinity will be supported since the use of nitrate increases alkalinity but the production of nitrate by nitrification no longer lowers alkalinity. It can happen that both Calcium and alkalinity will increase, so that we have to do little or nothing to correct this, depending on the calcification consumption.


In an SBNMS (sulfur based nitrogen management system) alkalinity and calcium corrections may be less common as may be expected in a normal reef aquarium.

 

[purp]

So just my initial observations, my starting NO3 was 10 ppm. After adding the sulfur in a passive filter sock, there has been a decrease to 5 ppm nitrate which has held steady. There has been some consumption of alkalinity, on the order of 20-30 mL of alk solution each day. No notable effect on pH.

 

[Belgian Anthias]

So just my initial observations, my starting NO3 was 10 ppm. After adding the sulfur in a passive filter sock, there has been a decrease to 5 ppm nitrate which has held steady. There has been some consumption of alkalinity, on the order of 20-30 mL of alk solution each day. No notable effect on pH.

Did you mix any calcium carbonate with the sulphur?

 

[purp]

Nope.

 

[purp]

I just wanted to update again here. Zero problems with my setup. No water changes in months, I feed 2 cubes a day and have a light to moderate fishload with enough algae to keep two tuxedo urchins happy in the DT. My nitrates are almost never above 2 ppm. I would say that thus far the sulfur sausages have been very effective and have not had any noticeable deleterious effects.

 

[Belgian Anthias]

I just wanted to update again here. Zero problems with my setup. No water changes in months, I feed 2 cubes a day and have a light to moderate fishload with enough algae to keep two tuxedo urchins happy in the DT. My nitrates are almost never above 2 ppm. I would say that thus far the sulfur sausages have been very effective and have not had any noticeable deleterious effects.

Thanks for the info!
As no calcium carbonate substrate is mixed with the Sulphur it would be interesting to be able to compare the alkalinity consumption. It was 20-30ml Alk solution daily. What Alk solution is used? Total system volume?

 

[purp]

I use an alk solution of 65 g/L of sodium bicarb. Total system volume is probably 200 gallons.

 

[Belgian Anthias]

I use an alk solution of 65 g/L of sodium bicarb. Total system volume is probably 200 gallons.

Did you follow up on the evolution of the calcium content? How much is the normal calcium consumption and how calcium consumption is corrected?

 

[Belgian Anthias]

I personally do not have a long term experience using BADES rolls without calcium carbonate mixed with the sulfur substrate. I think a lot less Sodium bicarbonate will be needed. Calcium production is considered to be a positive thing and as we grow algae in a refuge if needed we can grow Halimeda to correct calcium.

 

[purp]

i dont have any coral in my display tank at the moment, so my Ca demand would be negligible. I actually haven't tested my Ca in the display tank, but I can do that this evening. I will be interested to see how that's going. I'd expect it to be higher than "ambient" ca provided by fresh saltwater.

 

[purp]

i just tested it. it's 414 ppm .