Sulfur Reactor Questions

[Napoleon I]

I am in the process of setting up a sulfur reactor in my 125 gallon reef tank. I have found the sites with directions to build one but I have a few questions for those with experience that I was unable to find answers to.

First:
Most all designs I have seen have a valve at the top to relieve pressure daily and not let any oxygen into the vessel. Has anyone use a fermentation lock like you use in beer and wine making? It seems to me it would work just fine in keeping the oxygen out while still allowing the vessel to rid itself of gases built up by the reaction. Anyone have any input as to why this would not work?

Second:
The DIY site list the beginning flow rate as a drop per second. But then goes onto say after it is settled in the flow rate should be 3-4 lph.
Well a drop of water is generally considered to be 1/20 of a ml. So a drop per second is 3ml per minute or 180ml per hour. This is a far cry from 3-4 lph. So is the starting flow rate too low or is the 3-4 lph too high? I understand it has to be adjusted depending on nitrate levels etc.. But I am looking for a DC powered peristaltic pump to dose the tank water into the reactor and I need to be certain I have the anticipated range of flows accounted for. Any help would be appreciated. Maybe some numbers of flow rates from those that are using one would be helpful.

Thanks in advance!

Jeff

 

[AcroporAddict]

Most of the commercially made units do not have a release valve for nitrogen gas buildup, because a properly designed sulfur denitrator should not need one. Nitrogen gas produced should exit the denitrator via the effluent port, which, in most units is located at the highest liquid point in the reactor, so any N2 gas that bubbles out would find the effluent port anyways.

A fermentation lock is fine as long as it does not let O2 into the denitrator, but it may not be needed as a part of the design.

The effluent rate you can push through a denitrator is dependent on some things:
1. Desired NO3 levels
2. Sulfur volume in the reactor.

You can only flow so much tank water through a given sulfur volume before the facultative bacteria in the reactor switch from NO3 to O2 for their oxygen. They can use either, and by setting up an anoxic environment in the denitrator, we force the bacteria to get their O2 from nitrate, instead of the much easier method of just pulling dissolved O2 out of the water.

Start a new denitrator at 1 drop/second, then when the nitrate level of the effluent drops to zero, increase it by one drop/second, then when the nitrate level of the effluent effluent reaches zero, increase it by 1 drop/second again. Repeat until your effluent rate maintains your desired tank nitrate levels, or you cannot push the effluent rate any higher without getting measurable nitrates in the effluent. If you are unable to push the effluent rate any higher to get your desired NO3 levels in your tank, then your sulfur denitrator sulfur volume capacity is not large enough for the amount of nitrate your reef is producing, and you need a larger volume denitrator.

I have a 465 gallon SPS tank and do not use a refugium, and have minimal live rock compared to the total volume in my system, maybe 275 pounds of LR in 450 net gallons of water. I also have many large fish in this tank. I have a custom built recirculating GEO sulfur denitrator with about 5 gallons of sulfur media in it, or 1% of system net volume. I run an effluent rate of about 420 ml per minute through it, and this gives me almost undetectable nitrate levels in my system.

So, if you go the DIY route, make sure you have a quality recirculation pump on your denitrator, I would make it large enough to hold 1% of total system volume of sulfur media. Start with whatever amount of sulfur you wish. You can always increase the amount later if you wish. I added media two times during the fine tuning of my denitrator. Better to have the needed sulfur media capacity and not use it, than to find you have to build another reactor to replace the one you made too small the first time.

 

[rclendan]

I have a smaller PVC/DIY unit that has a twist air valve that came with the power head on the top to let the gas out. Some sort of valve is needed because the unit produces N2 gas that will create head space.

As far as the flow rate, I get about 3 liter/hour from my unit. It has about 1 liter of sulfur prills purchased on Amazon, and about 2 liters of aragonite media. I mix the media because I found the prills are too densely packed and clog unless if I mix them with the coarser aragonite (this would not be a problem with sulfur beads or pearls). To make the unit more adjustable, I added a plastic needle valve from US Plastics (this is a must have IMO). One drop per second is normal for cycling for the first 3 days, then as AcroporAddict said, once your effluent NO3 is zero, add a drop per second and wait for the unit to catch up. You will max out at some flow based on your media volume and internal oxygen level. Keep in mind that these units can be too big, the problem is that a too large volume of sulfur media will require a lot of nitrate fuel, but when the nitrate drops, the bacteria will starve and start feeding on the sulfur requiring you to speed up the unit which causes increased O2 levels that could stop the bacteria from using NO3 for respiration. You must then remove some of the media to operate at very low NO3 (or dose nitrates, I guess). The positive side is that once the unit is initially cycled it is fairly quick to restart. Mine takes about 12 hours to restart after opening it. I add a pinch of sugar to the unit before I close it up to speed up oxygen consumption and the re-cycle.

Sulfur denitrators work great. At 3 liter per hour my heavily fed, 120 gal total volume aquarium/sump/refugium gets completely processed in about 7 days which is more than enough flow to keep my tank at or near 0 nitrates.

 

[AcroporAddict]

I have a smaller PVC/DIY unit that has a twist air valve that came with the power head on the top to let the gas out. Some sort of valve is needed because the unit produces N2 gas that will create head space.

As far as the flow rate, I get about 3 liter/hour from my unit. It has about 1 liter of sulfur prills purchased on Amazon, and about 2 liters of aragonite media. I mix the media because I found the prills are too densely packed and clog unless if I mix them with the coarser aragonite (this would not be a problem with sulfur beads or pearls). To make the unit more adjustable, I added a plastic needle valve from US Plastics (this is a must have IMO). One drop per second is normal for cycling for the first 3 days, then as AcroporAddict said, once your effluent NO3 is zero, add a drop per second and wait for the unit to catch up. You will max out at some flow based on your media volume and internal oxygen level. Keep in mind that these units can be too big, the problem is that a too large volume of sulfur media will require a lot of nitrate fuel, but when the nitrate drops, the bacteria will starve and start feeding on the sulfur requiring you to speed up the unit which causes increased O2 levels that could stop the bacteria from using NO3 for respiration. You must then remove some of the media to operate at very low NO3 (or dose nitrates, I guess). The positive side is that once the unit is initially cycled it is fairly quick to restart. Mine takes about 12 hours to restart after opening it. I add a pinch of sugar to the unit before I close it up to speed up oxygen consumption and the re-cycle.

Sulfur denitrators work great. At 3 liter per hour my heavily fed, 120 gal total volume aquarium/sump/refugium gets completely processed in about 7 days which is more than enough flow to keep my tank at or near 0 nitrates.

If a DIY design makes nitrogen gas that is unable to pass out with the effluent, then by all means use an escape valve. But, a properly located effluent port negates the need of this. I don't have one in my reactor, or any of the other two I have used (GEO, Midwest Aquatics and Korallin). The nitrogen gas leaves with the effluent.

The amount of sulfur is independent of the nitrate level. If you have too low a nitrate level in the tank, you just lower the flow rate through the reactor, and the bacteria population will lower to adjust to the amount of nitrate being flowed through the reactor, and after a period of time the nitrate level in the tank will rise as a result. It is not necessary to remove any sulfur media.

The time the actual volume of sulfur media can be an issue is if you do not have enough in the reactor, as this limits the available surface area for the denitrifying bacteria to colonize.

Also, the denitrifying bacteria do not switch to consuming sulfur if the nitrate level in the reactor is too low. They consume the sulfur as part of their normal process, regardless of the amount of nitrate being fed to the reactor. The bacterial population in the reactor just decreases to a lower level of nitrate in the water passing through the reactor. They always consume sulfur in the denitrification process, regardless of the nitrate level in the reactor. They do not consume sulfur as a response to lower O2 levels. They use the sulfur as an energy source to break the NO3 bonds and liberate O2 for their use, which, in turn, releases nitrogen gas, which then passes out of the reactor with the effluent. The purpose of the sulfur is to provide that energy source, in addition to providing surface area for the facultative bacteria to colonize.

The bacteria population in the reactor will rise or fall to meet the amount of nitrate being fed to them, which is regulated by the volume of water being fed into the reactor.

I take apart my denitrator once a year or so and rinse the media, as over time the dead bacteria detritus inside the reactor can start to clog up the reactor. The detritus looks like white oatmeal floating in the water. I just rinse/drain until the water runs clear, then restart the denitrator. There are enough bacteria left on the sulfur to quickly cycle the reactor again.

 

[rclendan]

I could combine the gas with the effluent line, but I don't because of my installation is easier with a side port that is below the high point. The important point is the gas must escape somehow.

There is a definite corellation to H2S production and flow rate but it is probably due more to oxygen availability than NO3 availability. If the unit is turned down too low, the bacteria will start to cosume Sulfur under anearobic condidtions and produce H2S, but this will not happen under normal anoxic flow rates.

 

[AcroporAddict]

f the unit is turned down too low, the bacteria will start to cosume Sulfur under anearobic condidtions and produce H2S, but this will not happen under normal anoxic flow rates.

Regular cleaning of the sulfur media every 10 months to a year prevents this, IME.

 

[Greg 45]

Acropor Adddict can you please post a picture of your reactor.
I just had one built by Bill Wann for my 1200 gal system.

 

[AcroporAddict]

Acropor Adddict can you please post a picture of your reactor.
I just had one built by Bill Wann for my 1200 gal system.

Here you go. This was right after I set it up. I have since replaced the calcium reactor media with additional sulfur, for a total volume of about 5-5.5 gallons. So just picture it completely filled with sulfur.

 

[purge43]

My rx is almost identical to the one above, except for two things. My discharge fitting is on the top facing upward which allows me to have no concern for gases building up in the chamber. The discharge fitting in the above pic shows it not at the highest point of the water level, providing a place for gasses to build up. I cut my downward return pipe (the black pipe in above pic) and spliced in a 4 inch pc of clear hose with hose clamps and pinched a piece of teflon tape under one of the hose clamps with the tape dangleing in the water flow to indicate proper pump function. I dont know if it has been mentioned or not, but during the set up you will see a high nitrite spike, I forget why, but be aware of it, it should not have any affect on DT since your only letting out drops. My first start up I did all that your doing, counting, timing, digiting and stressing. My second set up i basically just started out with slow drips and gradually increased it over about 3 months, until now I run a steady pencil lead stream. This device is the one main thing that has made the hobby affordable for me, after years of fighting nitrates with 50% wc's, I finally found something that works.

 

[AcroporAddict]

My rx is almost identical to the one above, except for two things. My discharge fitting is on the top facing upward which allows me to have no concern for gases building up in the chamber. The discharge fitting in the above pic shows it not at the highest point of the water level, providing a place for gasses to build up. I cut my downward return pipe (the black pipe in above pic) and spliced in a 4 inch pc of clear hose with hose clamps and pinched a piece of teflon tape under one of the hose clamps with the tape dangleing in the water flow to indicate proper pump function. I dont know if it has been mentioned or not, but during the set up you will see a high nitrite spike, I forget why, but be aware of it, it should not have any affect on DT since your only letting out drops. My first start up I did all that your doing, counting, timing, digiting and stressing. My second set up i basically just started out with slow drips and gradually increased it over about 3 months, until now I run a steady pencil lead stream. This device is the one main thing that has made the hobby affordable for me, after years of fighting nitrates with 50% wc's, I finally found something that works.

You are incorrect in your above statement about my denitrator. In my previous post I described it exactly as it is, at the highest point in the plumbing. You wrongly think the feed port is the effluent port. The line you were looking at (feed) is where water enters the sulfur denitrator, not where it leaves it (effluent). Maybe the below pictures will help you understand.

 

[AcroporAddict]

duplicate

 

[hoaglanddiver]

Does anyone know of an automated/electronic drip counter? (would think similar to electronic bubble counter for CO2 that some use for Calc Reactor)

 

[Napoleon I]

I put what is called a Rotameter on mine. It even has a valve to control it. And an easy to read scale with a float that indicates flow rate down to 20ml per minute. I am using model MMA-37. It is around $20 and works awesome.
www.dwyer-inst.com

Jeff