Which ORP Meter to Interface with Sulfur Reactor

[justonwo]

I have a sulfur reactor with a port that will allow me to insert an ORP meter, but I don't have any specs on which probe will fit in the fitting. I imagine it's pretty standardized.

Does anyone know which of these two ORP meters will seal properly in a sulfur reactor fitting?

https://www.amazon.com/Milwaukee-Po...=8-2-spell&keywords=millwaukee+orp+meter&th=1

OR

https://www.amazon.com/Milwaukee-50...92&sr=8-1-spell&keywords=millwaukee+orp+meter

Or are there any other suggestions. I just want something inexpensive and workable. Here is my sulfur reactor.

 

[Terence]

Who's reactor is that? I like it.

 

[Ikserk]

Looks like one of Bill Wanns. Aquarium Engineering is the company

 

[mcarroll]

Similar to the old Reef Dynamics reactors if memory serves.

Ignorant question: Don't you want a pH probe vs an ORP probe?

 

[justonwo]

No, it's definitely ORP. You want to ensure there is a reduction potential to facilitate the nitrate reduction reaction.

 

[mcarroll]

Are you essentially monitoring the effects of flow through the device with an ORP meter?

Apologies to the OP if these questions are in the way...

Is it not a CO2-based reactor? If so how do you not overdose without watching pH? This seems to be a major problem for folks who run calcium-based media...so I'm curious.

 

[justonwo]

Guys, I'd be happy to discuss the chemistry but I really just need an answer to my question about the probe. It's a sulfur reactor that is designed to cultivate anaerobic bacteria in a reducing environment. Such an environment is required if you want to reduce nitrate to N2.

 

[justonwo]

Are you essentially monitoring the effects of flow through the device with an ORP meter?

Apologies to the OP if these questions are in the way...

Is it not a CO2-based reactor? If so how do you not overdose without watching pH? This seems to be a major problem for folks who run calcium-based media...so I'm curious.

Yes, precisely. You adjust flow to maintain a reducing environment. Initially, while the bacteria populations are small, the flow is very low. You ramp up slowly but with the goal of always maintaining a reducing environement. The reactor does tend to drop pH, which is the reason for the coral media on top.

 

[mcarroll]

So the sulphur is just a growing medium, not one being dissolved by CO2 additions? Huh.

Doesn't seem like there's much cost difference between probes, so whatever makes sense. But couldn't you use a pH probe since the bacteria do have an acidifying effect? I only ask cuz of the reputation that ORP monitoring carries for being unpredictable and sometimes nonsensical. Is it a stable situation when you're only monitoring a reactor vs a whole tank? (Seems like it could be.)

 

[Terence]

Use an apex and simply reverse the polarity so you can get the negative ORP values. There are adapters I think that do this for BNC connections or, if you are good you can splice or terminate a new BNC with wires reversed.

 

[justonwo]

It's still too early to tell. My biggest problem is that the flow won't remain steady. If I set it to a very low flow, it reduces to no flow by the following day. The ORP meter is helpful in that it gives you a better gauge than the NO3 measurement and is much easier to follow. I got a little worn out doing nitrate tests.

It also gives you a better idea of the magnitude of the reduction potential relative to other settings. It'll be helpful to understand the magnitude of changes that can be tolerated while still maintaining a reducing environment.

 

[Jeffdstafford]

To answer your question (if I'm not too late) , any readily available ORP probe should be the same size and fit that port fine. I'm running the system you're talking about, so I'll offer my experience and hope it helps. I set it up about 4 months ago on my 500 gallon reef, and now have all the kinks worked out. I'm running a variable speed Masterflex peristaltic pump that ramps up or down accordingly, but an on/off feed pump will also work fine.

Just FYI, and to save you some money, neither of those links you posted will work for this application IF you want to fully automate the control of the reactor, those are orp meters, and you'll need an orp controller to control a feed pump turning on and off. (however if you're just looking to passively monitor , then they are fine)

Do you have an apex? If so, like Terrence suggested, you can get some cheap fittings off amazon to create a crossover cable to allow the apex to read the value (it cannot read negative values like you'll maintain in a sulphur reactor) and you'll just reverse your setpoint programming accordingly.
-I can help with that programming if you go that route and need any assistance .

Other option I liked was a Milwaukee ORP controller, however you'll still have to make a crossover cable , because while the Milwaukee can read negative values , it cannot control off a negative setpoint, so you'll still need the crossover cable to get positive values.

Not hard at all to do, and I'm glad to help further if you need it. I would caution against trying to reverse the actual probe wiring and just make a BNC crossover..making a cable is much easier.

 

[Lasse]

Hi

If you need to regulate the flow like @Jeffdstafford says (and it’s a good solution) - just get a ProfiLux 3.x controller. It handles and controls negative readings of ORP. At one of my workplaces we use a similar filter as yours and monitor and control the ORP value with a profilux 3.0 system. A dose pump manage the flow. By the way – ORP negative readings is more stable compared with readings in the open water – and it works excellent to manage a denitrification filter of any type. Below you will see graphs of the readings of a system with a sulphur filter and the readings of the water below the membrane of my DSB with reversed waterflow. The redox level around – 170 mV seems rather good for a sulphur system. In my case I still testing how to optimize my DSB in different ways – just now I run a nominal value of -18 mV but I´m going to lower it by time.

One thing worth of mention is the fact that the Control Center of Profilux 3.x has a bug according to negative ORP. You can put a negative ORP in the field of nominal value but next time you start the Control Center it shows 0 mV. However – the web interface and also the original interface show the right figures and the computer has the right figure.


I also know people that use Apex and have change the polarity of the signal – its works also.


If you only want to monitoring the value – most standard probes should work. The critical parameter is (according to my thoughts) the diameter of the probe – it should fit in the port – they usually has a fitting that can take different diameters (in a short span)


Sincerely Lasse

 

[justonwo]

I was looking mostly for the diameter and it turns out the Milwaukee probe I picked was just the right diameter.

I'm not at the point where I want to setup a feedback look. I simply wanted a better guide for the startup process of the sulfur reactor. Once the reactor has reached a steady state, Bill Wann tells me it will run with the needle valve pretty much wide open.

 

[Jeffdstafford]

Good deal, that meter will definitely help immensely in dialing in your flow. Let us know if you run into stability issues maintaining the proper negative ORP and we can assist in setting up further automation . . But hopefully yours will function fine with open flow. Good luck , you'll love a sulphur reactor, such a simple way to combat nitrates!

I was looking mostly for the diameter and it turns out the Milwaukee probe I picked was just the right diameter.

I'm not at the point where I want to setup a feedback look. I simply wanted a better guide for the startup process of the sulfur reactor. Once the reactor has reached a steady state, Bill Wann tells me it will run with the needle valve pretty much wide open.