Sulphur denitrator for large setup

[CoryDude]

My opinion not enough sulfur may be used for a 700 gal system and reducing the level to below 1ppm would only be possible when the daily nitrate production is very low. When following the Koralin guidelines I do not see how this could be managed. Maybe a carbon based denitrator can be managed this way but certainly not a sulfur based denitrator. Hopefully I am wrong and can I learn something from your story. Using a sulfur denitrator system, it should be possible to have control over the nitrate level in the aquarium and keep it on the desired level, a big difference apposed to other nitrate reducing or removing methods who are only able to reduce nitrate, not control it.. Thanks.

Hello and welcome. I saw your post on a different thread of mine late the other night and would have responded had it not been so late. Always nice to have international visitors to our site.

You are completely correct in your opinion. I only ran mine on a 120 gallon system with about 1.9 liters of media. I've also only recommended them for low to medium bioload tanks.

When I did run one on a high bioload tank I ran into problems. It could not outpace the accumulating nitrates produced by the tank.

With a system like yours I would definitely recommend a carbon based filter.

[degrijze]

Hello and welcome. I saw your post on a different thread of mine late the other night and would have responded had it not been so late. Always nice to have international visitors to our site.

You are completely correct in your opinion. I only ran mine on a 120 gallon system with about 1.9 liters of media. I've also only recommended them for low to medium bioload tanks.

When I did run one on a high bioload tank I ran into problems. It could not outpace the accumulating nitrates produced by the tank.

With a system like yours I would definitely recommend a carbon based filter.

Hello and thanks for the response.

With a system like yours I would definitely recommend a carbon based filter.

I would never change a sulfur denitrator for a carbon based reactor. Carbon based reactors can reduce nitrate but can not control the level, biopellets are consumed and have to be dosed carefully. Needs daily attention. And most important, It would not be possible to have control over the nitrate level in the system as I have now using a sulfur denitrator..
VODKA based systems reduce nitrate by accumulation into the bioload but does not remove it. To remove the nitrate, this bioload has to be harvested before it dies.
Carbon based reactors can not remove high bioload at low nitrate levels because they can not handle the flow. There are some polymers on the market which have the need for very high flow to work but nitrate control is not possible using this system. They only can reduce nitrate, not controlling the level.

When I did run one on a high bioload tank I ran into problems. It could not outpace the accumulating nitrates produced by the tank.

A sulfur based denitrator is certainly capable to remove high bioload, even at very low nitrate levels. That is why we use 1% reactors. For a 120gal system we would use 1.2 gal sulfur. Quantity of sulfur is based on the daily to remove quantity of nitrate and the desired level of nitrate on which the reactor has to operate. Because animals grow and multiply the daily to remove quantity is variable. When a production of more than 1ppm daily has to be removed reactors of 2% may be considered when operation at low nitrate levels below 1ppm is desired. To reduce the nitrate level in the system from 1ppm to 0.5ppm the flow must be doubled to remove the same quantity of nitrate daily.
When the reactor is to small for the system one can be encountered by its limits. Most mistakes are made when used as a problem solver to reduce high levels. When the reactor is not big enough at some point the nitrate level will not decent any more because the reactor can only remove the daily production. With the same flow, the reactor is able to remove 2 times more nitrate at 30ppm as when a level of 15 ppm is reached. Flow has to be increased to enter more nitrate. When the reactor is to small it can not handle the increase in oxygen and even less nitrate will be removed. When the flow is mismanaged at that point and decreased to create more anaerobic space, as less nitrate is entered and more anaerobic space is created the system may become anoxic and start to reduce sulfate making H2S. When the flow is reduced more the oxygen reducing bioload will die off and one may conclude a sulfur denitrator does not work. When using a reactor that is big enough all of this is avoided and nitrate levels can be decreased smoothly by increasing the flow to below 1ppm without being encountered by the reactors limits.
This when fluidized bed reactors are used.

What is the max flow your denitrator can handle at the nitrate level it is operating and how much is this level? Any idea of your daily to remove quantity of nitrate?

[degrijze]

It works. My bio load is huge. I feed my sharks/eels 5 sardines about 9" long every 2-3 days. I also feed whole octopus, squid and other fish. Ive had about 5-10ppm with out doing anything to the aquarium for 1 year. I finally did a water change, clean the rocks and stirred the sand. I have yet to check the new levels. Ive used about half the sulphur that came with the unit. It was frustrating getting it to work but now its eaay. Hardest part is priming the pump. Im happy with it.

Thanks for the response.
Why did you only use only half of the sulfur? What is the reason? How much sulfur in volume do you use for the moment? For example I would use at least 7 gal sulfur for a 700 gal system. If a level of 10ppm is ok , this amount may be reduced. Most would like to keep a much lower level.

[CoryDude]

There is a high flow carbon based filtration system called a hiatt filtration system. But it requires massive amounts of carbon and a high flow pump.

Removal rates depended on the system variables. On a new start up on my 120, I ran a diy dual reactor with about 5 liters of sulfur media with peak no3 levels of 40ppm. At about 2 drops per second, it had no3 levels down to 20ppm after 3 weeks, and then dropped the remaining levels to 1-2 ppm after another 2 weeks.

Flow was upped to 3-4 drops per second after 15 ppm and the volume of media was reduced to 2.5 L.

[glarior]

Thanks for the response.
Why did you only use only half of the sulfur? What is the reason? How much sulfur in volume do you use for the moment? For example I would use at least 7 gal sulfur for a 700 gal system. If a level of 10ppm is ok , this amount may be reduced. Most would like to keep a much lower level.

i used the full amount that came with the kit. However when i cleaned it only 1/2 of the sulphur remained. I need to buy more. Website says 1.6kg of sulphur

[degrijze]

There is a high flow carbon based filtration system called a hiatt filtration system. But it requires massive amounts of carbon and a high flow pump.

Removal rates depended on the system variables. On a new start up on my 120, I ran a diy dual reactor with about 5 liters of sulfur media with peak no3 levels of 40ppm. At about 2 drops per second, it had no3 levels down to 20ppm after 3 weeks, and then dropped the remaining levels to 1-2 ppm after another 2 weeks.

Flow was upped to 3-4 drops per second after 15 ppm and the volume of media was reduced to 2.5 L.

We would have used for this system 5 litre sulfur also = +- 1% of +- 450 litre not knowing the daily nitrate production.
The system has very low daily nitrate production keeping 2 ppm with a flow of only 3 to 4 drops/sec ( +- 20ml/min or 1.2l/h) It may be estimated to be +-60mg or 0.14ppm nitrate daily which is not much. When 1 ppm can be maintained at this drip rate this means the daily production may be only 30mg or 0.07ppm/day.
Removal rates depends of the flow and the nitrate level in the system. When the Sdenitrator is used as a problem solver, this means to remove high nitrate levels, flow should follow the nitrate level to feed the reactor enough nitrate when the nitrate level in the system level descends.
During operation this system should be able to handle a flow that is 5x higher and a lot more. When flow is not adapted to the nitrate level the risk for H2S production increases. At 40ppm and a drip rate of 2 drops/sec the reactor is removing +- 700mg nitrate daily. As this reactor can easily remove 5000 mg nitrate daily and a lot more the capacity is not used. Not enough nitrate is entered. At this drip rate most of the reactor is anaerobic but not enough nitrate is available to fill up the space with denitrifiers. As the level goes down because only 60mg nitrate is produced daily and the flow is not corrected ( increased!) the risk for this reactor to become critical increases when nitrate level goes down. This makes the reactor vulnerable for mismanagement and this reactor may crash due to not enough nitrate availability for to much anaerobic space. Running a 5 litre reactor at a drip rate of 2 drops a second seems to me a risky business. I would run it at much higher flow. To be honest, I am amazed this works so well. Sdenitration systems seems to be less vulnerable and more crash resistant than I thought. We have always advised to use 1% reactors to be able to remove high bioload at low nitrate levels ( +-1 ppm daily at a nitrate level of <1 ppm) and 1/2 % reactors when used to remove less than 1ppm daily or maintain a level between 1ppm and 2 ppm. For this system , with an estimated daily nitrate production between 30mg and 60 mg ( between 0.14 ppm and 0.07 ppm) 1 littre sulfur would have been sufficient to reduce the level and keep it at +-1ppm .
We have always advised to use sulfur reactors that are big enough to avoid managing problems when used as a problem solver. Flow management is the main factor. Used as part of the system a correct based Sdenitrator is self-regulating. Once the flow and the reactor is in balance with the system there is not much to do to keep the desired nitrate level.
Knowing the normal daily nitrate build up in the system before starting to use a Sdenitrator is the key factor for determining the sulfur quantity needed. .
Comments?

[degrijze]

i used the full amount that came with the kit. However when i cleaned it only 1/2 of the sulphur remained. I need to buy more. Website says 1.6kg of sulphur

it is important to know how much sulfur is used in volume( liter, Gal) not in weight ( kg). The quantity sulfur needed is determined in volume.
It is also important to have an idea of the daily nitrate production which has to be removed daily. With the device in use this can be determined using it. Bring up the reactor to its max capacity, increasing the flow until the effluent does not stabilizes at O any more. Decrease a little bit till 0 effluent. This may take a few days. Than leave it. When level descends, more than the daily production is removed. At some point the nitrate level will not descend any more. Only the daily produced quantity is removed. Multiplying the daily flow with the nitrate level in the system will give the daily nitrate production. At this point flow should be increased to enter more nitrate. if this can not be done having 0 nitrate in the effluent a few days later the max capacity of the reactor is reached. The reactor is not big enough to reduce the nitrate to a lower level. Do not start decreasing the flow at this point because it will kill the beasts. Just a little bit to eliminate possible nitrite production.( which is not a problem). This is how I would do it.
When the daily production is known and the desired nitrate level in the system is decided one can determine the quantity of sulfur needed . When these parameters are not known a 1% reactor is advised.
Any container that can be closed air tight can be used to build a fluidized bed reactor, this for a few dollar.