Sulfur Denitrator: Who's running one?

[Phyl]

I'm interested in hearing from those who are running a Sulfur Denitrator. Which one do you have? How is it working for you? Pictures would be great. Is there a need for the water to be O2 deprived going into the reactor? What are the pros of the unit you're using? Cons?

 

[RichT]

I'm using sort of one until I get a DIY made. I have a phosban reactor filled 2/3 with sulfur beads, 1/3 argonite. That reactor is first inline with a phosban reactor filled with carbon then another filled with phosban. I have enough flow going through the reactors that the phosban is lightly churning on the surface. 4 - 6 week ago my Nitrates were 15-25. I just checked them yesterday and they are around 1.5 - 2.5. I'm using Salafert <sp> test kit using the side view / low range method. I know it's somewhat anecdotal but I think it's working well enough for now that unless the nitrates rise or some other problem arises, I may scrap the DIY build.  HTH

 

[Phyl]

Nice. Thanks, Rich!

 

[Phyl]

What's your drip rate on that coming out of the reactors (or is it a normal outflow for the Phosban style reactor)? Is your effluent hose under water or above the water line? Are you running it through black tubing first to reduce the O2 content of the feed water?

 

[ndas2976]

I'm running the midwestaquatic sulfur denitrator. The unit is built very well, has John Guest valves and the sulfur come prepopulated with bacteria to get the unit to cycle quicker. The unit seems to work good, I just can't seem to get the drip rate above 3dps without registiring the slighest nitrite, but Rick from Midwest is working with me on that. The company has out standing customer service. You could check out the forum on thier website and look for my screen name.

www.midwestaquatic.com

 

[RichT]

What's your drip rate on that coming out of the reactors (

normal phosban flow rate. 20 - 25± gal/hr.

Is your effluent hose under water or above the water line?

Above the water line.

Are you running it through black tubing first to reduce the O2 content of the feed water?

Straight from a MJ400 through standard braid reinforced clear tubing w/TLF mini ball valve to the triple inline phosban reactors.

Like I posted before my results are purely anecdotal. But there is no denying the dramatic reduction of nitrates since I set up the reactor. Now that I think about it, the reactor was set up a week or two after our previous PA group buy.

 

[Carlo]

I've been running nitrate reactors for as long as I can remember. I've done carbon & sulfur and prefer sulfur as I think it's easier. I have ORP probes installed in mine and use negative ORP readings to control the affluent. I keep mine nailed at -170mv.

IMHO I wouldn't even think of running one with an ORP controller. I used to think I could dial them in good but it's nothing compared to setting a specific ORP reading and having it stay there. Above -50mv (going towards positive) and you aren't doing anything, under -300mv and it's BAD, between -150mv & -200mv is pretty optimum.

Carlo

 

[Carlo]

RichT, You may be getting lower nitrates at the moment but it's not happening for the reason you think and you should probably stop using it the current way. With a flow that high (it's super high) there is no nitrate reduction taking place in the chamber. The water is going to have tank level ORP numbers in the reactor (high O2).

What instead is happening is sort of bad. The sulfur is providing a carbon source to the tank which is fueling additional algae growth and the algae growth is responsible for the reduction in nitrates & phosphates. Depending on how bad this is happening, you might be able to catch it with an ammonia or nitrite test kit. It sort of works on the same principle as sugar or vodka dosing only you are providing a carbon source based on sulfur.

If you check the affluent you'll probably see it not being zero.

Carlo

 

[RichT]

I'm sure your probably right with what your saying Carlo but as of right now, I have no nuisance algae, only cyno that I've had for longer than I've been running the sulfur, and its receding . As I've post above, my observations are purely anecdotal and until such time the nitrates rise, or something else becomes a problem, I'm going on the assumption that whatever it is that is going on is working for whatever reason. As soon as or if that happens, I'll jump right on board with your explanation.

Thanks.

 

[kabal2]

rich what kind of sulfur beads are you using??, if you have a website will be great
thank you

 

[RichT]

I got the Carib Sea stuff from Premium Aquatics. I don't see it being offered their anymore. They do have the stuff from Midwest though that would do the job.

 

[adesimone1]

We are running one we bought off the big auction site. It took about a week to get it set, and the trates went to zero. Starting out with a slow drip until the bacteria built up then once the trates jumped higher in the reactor we had to increase the flow then less then 6 hours the trates were at zero. And they have been good since then. We do a water change maybe once a month our corals are doing good fish are all healthy. And I don't have to add calcium because aragonite replenishes it thru the reactor. Best thing we ever bought. And the guy who sold it to us worked with us everyday until the trates went down

 

[Phyl]

Who did you buy it from, Adesimone?

 

[adesimone1]

I'll look it up in my email and I'll give it to you. Best money we ever spent. It is rated I think for 800 gallons.

 

[adesimone1]

pm sent

 

[Phyl]

Thanks, Adesimone!

I've read that you need to O2 deprive the reactor water to have the desired results. We were thinking about having a coil of black PE tubing going into the first reactor so that the water going in was O2 deprived (bacteria that builds up in the tube depletes the O2 before it hits the first reactor).

Carlo, how slowly would you start the PO4 reactor effluent?

 

[RichT]

I'm by no means advocating the method I'm using the media. So if anyone is going to try it I would highly suggest doing your homework. I was merely posting what I did and the results, again anecdotal.

Carlo - wouldn't I be able to smell the sulfur if the reactor was adding it to the tank? Thats what I understood from the limited reading I did. I check for both sulfur and ozone smell quite frequently since I've implemented both.

 

[Carlo]

Here's a few things learned from 20+ years of running Denitrifiers.
Denitrifiers are very simple devices with complex workings/tunings. They are basically calcium reactors without the CO2 rig attached.

A very economical reactor to use as a nitrate reactor is the Coralife Calcium Reactors which are available in 250 and 500 models.
http://www.marinedepot.com/aquarium_calcium_reactors_coralife.asp?CartId=
The rates above of 250 & 500 are when used as calcium reactors. In "nitrate" mode they will easily do 2x the volume listed (IE 500/1000).

These cheap reactors are available at many online retailers and at most lfs that stock any type of calcium reactor (cheap & easy to find). They feature a "pH probe port" built into the lid. This port can instead be used for an ORP probe and used to measure the REDOX of the reactor.

How Does the Sulfur Denitrifier work?
The Denitrifier works by creating anaerobic (low oxygen) conditions inside the unit. By
creating this environment, natural bacteria within the unit will break down the nitrate as water is passed through the filter. As water is trickled through the filter, nitrate is removed from the water and the water is returned to your aquarium. Nitrogen then escapes the water and enters the atmosphere by diffusing through the water's surface. Nitrogen gas is harmless, and actually makes up 78% if the earth's atmosphere.

Additionally, a Sulfur Denitrifier will add CO2 to the water, lower alkalinity and pH in the reactor as it's doing it's work. It is for this reason, that calcium carbonate is added to the reactor. The addition of calcium carbonate to the filter allows it to function not only to remove nitrates, but also to add small amounts of calcium to the aquarium, which is beneficial to corals and other animals that create calcium carbonate skeletons or shells.

Reactor Packing/Loading
Most "manufactures" will tell you to load the bottom half with sulphur and the top half with calcium carbonate. I don't recommend this. Since I started doing this before these things were being manufactured I learned many years ago that once the reactor is working well you DO NOT WANT TO TOUCH IT. Since you only need to add sulphur materials when it's low (once a year or two) this is easy BUT if you have to open the reactor every 6 weeks to 8 weeks to add more calcium carbonate you throw off the REDOX of the reactor and have to start over again tuning it (see below).

What I've found to work extremely well is to fill the reactor 1/2 to 2/3s with Seachem's Matrix. This stuff is awesome for hosting bacteria and it's shape is really good inside a reactor. (I have one long term running reactor running Siporax but the shape traps air bubbles and makes it harder) Then fill the rest with sulphur and DO NOT PUT any calcium carbonate in the reactor. You now have a reactor that won't need to be exposed to air for 2 or 3 years and has a ton of bacteria hosting surface area.

Next add some type of small reactor like a cheap phosban reactor or a DIY model. Nothing fancy needed and it DOESN'T need to be recirculating. What I do is pack this with calcium carbonate and have the output of the main sulphur reactor flow into this
reactor and then out to the sump. Using this second "reactor chamber" allows it to be filled with more calcium carbonate material whenever needed without any disturbance to the nitrate reaction chamber.

Tuning the Reactor
I don't recommend "gravity feeding" your reactor and instead would use an Aqualifter 3.5gph pump to supply tank water to the reactor. This just works better long term IMHO and the pump is cheap.

MANUALLY CONTROLLING REACTOR
1) Normally you would run the reactor open for 24 hours to flush the media and get any air trapped out of the media. It's helpful to "shake" the reactor back and forth a little at this point. (air in the reactor chamber=grief)

2) Next you would slow the drip rate down to 1 drip per second. After 2 or 3 days check the nitrate level of the effluent. Once it hits ZERO then

3) Adjust the drip rate up one drip per second. Check again in 2 or 3 days.

4) Repeat above steps by adding ONE drip per second while making sure nitrates at the effluent stay at zero.

If at any time you get a "rotten egg" type smell you should stop the reactor, empty it and start over. This is a bad situation and you could poison your tank. This can happen normally from neglect in setup and the drip rate wasn't adjusted correctly and is to slow for the amount of bacteria that has built up inside the reactor.

USING A CONTROLLER AND REDOX
This is my preferred method of running a nitrate reactor. In a nutshell you use some type of ORP monitor/controller to watch the Redox of the reactor. An ORP probe is placed in the reactor to achieve this (remember the calcium pH probe slot).

Using Redox reading to control/setup a nitrate reactor is so much easier. In a nutshell you want the Redox to be in the negative or below Zero. Anything above -50mv Redox tells you the nitrate reactor has to much O2 in the chamber and it isn't functioning correctly. Below -300mv is bad and is the same as the "rotten egg" mentioned above. The ideal range to try and adjust to is -100 and -250. From much experimentation over the years I've found -170mv to -175mv to be great target zones to shoot for.

ORP PROBLEMS & a LITTLE TRICK
Unfortunately many ORP devices will not read into the negatives. This goes for Neptune, Pinpoint and Milw. controllers.

It's very, very frustrating to have everything in place to use an ORP controller only to find out that your unit doesn't monitor below zero or does allow monitoring below zero but doesn't allow you to "controll" things based on negative values. The 3 brands mentioned above won't even read below zero.

You've seen me use mv (IE -170mv) in the description of redox values. It's a simple measurement of volts. The trick. Switch the wires around on the probe so the negative becomes the positive and vice versa. Now your equipment can "read" negative values but will show them as "positive". So when you see 100mv on the controller it's really -100mv. Once you get this concept you can use any controller and solenoid and/or pump to change the flow going into the sulphur reactor to keep it nailed at -170mv.

BTW, you don't literally need to hack up your probe to switch the wires. You can get a couple of bnc connectors at Radio Shack and build a crossover bnc connector.

Carlo

 

[Carlo]

Carlo - wouldn't I be able to smell the sulfur if the reactor was adding it to the tank? Thats what I understood from the limited reading I did. I check for both sulfur and ozone smell quite frequently since I've implemented both.

No, sulphur itself is orderless. I think you might be talking about the rotten egg smell which is "Hydrogen sulfide". Hydrogen sulfide often results from the bacterial break down of organic matter in the absence of oxygen in to little flow areas. The biggest areas you normally see this are in DSB down at the bottom. Typically the sand is very dark looking too. Normally you can't smell this in the tank itself until you are doing a tank breakdown.

In the case of a nitrate reactor you could possible smell it coming from the effluent tube and it would have the same "rotten egg" or "flatulence" type smell. In this case if it just started within a day just up the flow a few drips per second for a day and then re tune. If it's been this way "smelling" for a few days the reactor should be emptied/flushed and repacked to avoid crashing the tank.

In most cases if you had an ORP probe measuring these areas the ORP would be below -300mv to happen which is extremely O2 deprived water.

Honestly Rich, I don't know the dynamics of running the sulphur in the reactor at high flow rates besides the addition of a "carbon source" to the tank. There are a lot of dynamics going on in this. Since the reactor isn't very big and isn't recirculating and is only partially filled with sulphur it probably isn't leaching much into the tank. The little bit of break down of sulphur into the carbon source itself isn't going to be enough to cause a downward pH spike when the cyano gets limited. Large carbon source additions are notorious for pH crashes.

My best "chemistry" guess would be if you aren't using up your calcium carbonate quickly in the reactor (2 months or less) then it's not lowing pH in the reactor fast enough to do anything but release a tad bit of carbon over time. I can't really see much else happening good or bad.

BTW, you could probably make the phosban into a "true" nitrate reactor pretty easily. Hook a pump inline between the IN and OUT tubes up top and you have a recirculating reactor. Add a tap for an effluent drip on the OUT side and a tap for bringing in new tank water on the IN side. Then tune by the drop per second method or hook an ORP probe inline and controll that way.

You could even run multiple phosban reactors together but I wouldn't recirc the calcium carbonate at all. You could run sulphur in the first, followed by matrix in the second and run these two in recirc mode. That will give you lots of "surface" area for bacteria to grow in a low pH/oxygen environment and would rival much bigger reactors based on only sulphur and calcium carbonate.

Then run some type of small reactor with calcium carbonate in it to bring the pH back up from the nitrate reactor. This doesn't have to be a reactor and could be a 20oz cup while small holes punched in the bottom. You just want to drip the effluent of the reactor into/onto the calcium media to bring the pH of the effluent back up. It's also a decent idea to drip your effluent near your skimmer so the effluent gets oxygenated too.

Carlo

 

[Phyl]

Thanks Carlo. Most posts on RC talk about O2 depleting the water before it goes into the reactor. Why do you think that isn't necessary with the way you run yours? Would the recirc not be necessary if you coiled the in feed for say 100' before you hit the reactor? Seems to me lots of reactors run without the recirc (including the ebay model that adesimone is using successfully).

We may well pick up one of those Ca reactors while we're at THR today so that we can go the ORP route since we have an ORP probe lying around anyway, but I'm curious as to why there are continued successes with such a varying array of implementation methods.

Would coiling the infeed be beneficial to the recircing reactor method? Seems like a logical step in the process since you want that reactor chamber to be O2 deprived.