# pH controllers



## larusaquarium (Feb 21, 2015)

I have been watching some youtube videos and reading up some articles about pH controllers. Do you guys own pH controllers (I know some do), if so whats a good reputable brand ?
Is Milwaukee mc122 a good pH controller?
What are the pros and cons of pH controller? 

This might be a dumb question so don't get mad :hihi:
How does a pH controller work?


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## natebuchholz (Sep 28, 2013)

I have seen many people use the Milwaukee controller, I have not personally, but this seems to be a good indicator of their quality. 

Pros: Constant water parameters, both co2 concentration and PH, piece of mind

Cons: Cost of equipment, learning curve, extra equipment.

There are no dumb questions. 
I will try to answer to the best of my ability. 

A ph controller measures ph through a probe that has been calibrated with a known solution. This probe is placed into your water and constantly monitoring your waters current ph. PH is an indicator of the relative co2 concentration in your aquariums water. When dosing pressurized co2 people want to see a drop of 1.0 in PH before their lights turn on. With the controller you can set it to keep your tank constantly at that mark of 1.0 degree below your standard without co2. This way there is no ramp up and down and zero fluctuation between night and day and a constant optimum concentration of co2 for your plants.

I hope my rambling made sense.


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## loach guy (Jun 2, 2014)

I own a Milwaukee PH controller. I forget the model number, but it's the older version of the one that you are looking at. Mine works fine. You don't really need to ask it to do too much. The pros for a PH controller are that it's automated. You set it, and you forget it. The only con I can think of is if you have a situation like mine. My PH creeps up throughout the week, so since the controller is automated, it tries to drive the PH down a little too much. It's not that big of a problem as I have balanced it to an acceptable setting.

The way a PH controller works is that there are 3 components. The controller unit (brain), the PH probe, and the relay power outlet. You need to keep your PH probe wet at all times (there is a cap that slides over it that makes this easy to do). This is what goes in the tank and takes your readings and sends that information to the controller. You set your controller at a desired level. Most people shoot for 30ppm CO2 by measuring and doing calculations (there are threads on this forum for that). There are many too that pump as much CO2 in their tank as they can without distressing their fish (this is the rout I went). Your setpoint on your controller usually ends up being about 1.0 lower than your water in your tank. So say your tank is usually at a PH of 7.3, then your setpoint may be around 6.3. Let's use this an example. If your water is at a PH above 6.3, then your controller is going to close the relay that allows power to go to your solenoid on your CO2 system, which allows the CO2 to flow from your CO2 tank, into your aquarium. The way to control when all of this happens is by simply plugging in a timer into the relay power outlet from the PH controller, and plugging your solenoid valve into the timer. Once your PH controller senses that your water has hit your PH setpoint (in this case 6.3), then it opens the relay back up, and power is cut to the solenoid valve, and CO2 flow is stopped. It is a whole lot easier than it sounds. If you can hook up a blue-ray player, than you can do this.

If you are going to be injecting CO2, then this is DEFINITELY the way to go. Good luck to you. PM me if you have any more questions.


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## Malakian (Aug 23, 2014)

I just wanted to add, that it might lead to unstable Co2 concentrations. As KH isn't always constant. Stones, substrates and what not can affect the KH, and if you dose any KH raising products, you will have to be pretty accurate in the ppm to not make the Co2 fluctuate and reset the PH controller either +/-. This is just my experience with my controller, and 0-1kh out of the tap water. I have a Dupla controller though, but don't think that would make a huge difference

bump: That made me thinking all of sudden, is there a sensor that can measure KH? Maybe it would be possible to make some audrino controller that would make the PH and KH meter talk to each other. Now that would be a set-and-forget setup. -Did a little research, seems there is some KH probes available from some Chinese sources, but those are rather expensive. Guess we will have to wait a couple of years.


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## roadmaster (Nov 5, 2009)

Might google "pH controller vs drop checker in the aquarium for some enlightenment.


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## Coralbandit (Feb 25, 2013)

I have an older milwaulkee.8-10 years old with new probe.
No problems with it.
They are a HUGE safe guard IMO.
They also eliminate the possibility of End Of Tank Dump over gassing and deaths.
Once correctly adjusted there is nothing more to do ever besides calibrating the probe if necessary.
I run mine on a timer to turn on 1 hour before lights go on , and off 1hour before lights go out.


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## natebuchholz (Sep 28, 2013)

Malakian said:


> I just wanted to add, that it might lead to unstable Co2 concentrations. As KH isn't always constant. Stones, substrates and what not can affect the KH, and if you dose any KH raising products, you will have to be pretty accurate in the ppm to not make the Co2 fluctuate and reset the PH controller either +/-. This is just my experience with my controller, and 0kh out of the tap water.


This is true but, anyone who has a KH above or around 4dkh should be fine. At those levels ph is pretty stable any you should not see much fluctuation.


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## Malakian (Aug 23, 2014)

natebuchholz said:


> This is true but, anyone who has a KH above or around 4dkh should be fine. At those levels ph is pretty stable any you should not see much fluctuation.


Yes, thats true. But maybe I didn't make myself clear on what I meant, english is not my main language 

Example; If you have ADA aquasoil, and say you add 4kh water to the tank. 1 week later, the substrate would of leech most of the KH from the water, leading to a much lower concentration of co2 than you would think. As your KH would maybe just be 1-2 at that point.

Example 2; Like me to raise my KH, I use NaHCO3. When I do WC I pump out the water, and use the tap to fill it back up. To get a accurate KH, I need to take evaporation at the point of the WC into consideration to estimate how much water I put back in, which also will fluctuate with temps and humidity in the air, to get the right amount of NaHCO3.

Bump: If you just dial in the regulator, its will be supplying a constant amount of co2 (say 5ml pr hour, instead of 5ml pr hour 1 day, 4.8ml the next, 4.6 the day after that and so on) no matter what other water parameters is going on, leading to a much more stable co2. But it can be a pain to dial in the regulator.


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## FatherLandDescendant (Jul 24, 2014)

My mc122 works well I'm really glad I bought it when going to pressurized CO2. It should be calibrated once a month or so so I would suggest getting a bottle of 7.0 and 4.1 calibration solution, I don't use the Milwaukee brand but I do get lab grade solution, it's not that expensive.

Don't see much of a learning curve as another poster stated it's pretty stright forward as I see it.

As to this statement; 



> The way to control when all of this happens is by simply plugging in a timer into the relay power outlet from the PH controller, and plugging your solenoid valve into the timer


My solenoid has an equipment ground (the 3 round one on the bottom of a plug) on the plug, my timer isn't equipped for the equipment ground and most home timers that I've seen, and all the ones that I personally have owned, do not have the equipment grounded socket for the barreled connector. I (when I was timing my CO2) plugged the controller itself into a timer and plugged the solenoid into the relay, plugged the relay into the power strip of my tank. Besides I've seen to many people have reported to many problems with their solenoids that end up being incompatibility issues with their timers for me to want to plug my solenoid into a timer, just shut the controller off and the solenoid will follow.


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## Malakian (Aug 23, 2014)

roadmaster said:


> Might google "pH controller vs drop checker in the aquarium for some enlightenment.


Might want to google Tom Barr and Amano + ph controller


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## roadmaster (Nov 5, 2009)

I have read much about the topic in preparation for trying the gas and to become educated as to possible problems BEFORE they present themselves.
As I understand it.pH controller regulates CO2 release which is directly related to the pH.
Many things used in the tank or otherwise present, will have affect on the pH that affect's the amount of gas being released.
Things like GH booster,Magnesium,phosphates,pH up or down product's,equillibrium,and or acids such as humic acids will influence the controller as the pH is also influenced NO?


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## natebuchholz (Sep 28, 2013)

^ this is correct. It makes all of its decisions based upon a calibrated probe.


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## roadmaster (Nov 5, 2009)

I think I shall rely on drop checker with distilled water inside and known KH.
In this way,the pH of the tank will have no bearing, and I can see the color change only as a result of the CO2 present in drop checker.
This ,along with watching my fishes and plant's.
But I am still researching/learning and am open to other views from those with more experience with the gas.


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## lksdrinker (Feb 12, 2014)

I too am a bit lost when it comes to PH controllers. Since I've got three tanks running off of a CO2 manifold (currently anyway....maybe more to come), it seems a bit more difficult for me. 

Is it possible to use a ph controller on multiple tanks like this?

Do you run the controller on a timer so it can never turn on when the lights are off?


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## natebuchholz (Sep 28, 2013)

lksdrinker said:


> I too am a bit lost when it comes to PH controllers. Since I've got three tanks running off of a CO2 manifold (currently anyway....maybe more to come), it seems a bit more difficult for me.
> 
> Is it possible to use a ph controller on multiple tanks like this?
> 
> Do you run the controller on a timer so it can never turn on when the lights are off?


I believe it would be difficult to run a controller on a setup like that. 
Many people will leave the controller on all the time to keep a constant concentration as well as ph but I have also seen people use it with a timer; as you would if you were only using a regulator and solenoid.


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## loach guy (Jun 2, 2014)

lksdrinker said:


> I too am a bit lost when it comes to PH controllers. Since I've got three tanks running off of a CO2 manifold (currently anyway....maybe more to come), it seems a bit more difficult for me.
> 
> Is it possible to use a ph controller on multiple tanks like this?
> 
> Do you run the controller on a timer so it can never turn on when the lights are off?


You really should run your CO2 on separate systems. Personally, I would only have the outlet coming off the CO2 tank run to a manifold, and have separate regulators going off of that. That way each system is independent. What is good for one tank, may not be right for another.


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## lksdrinker (Feb 12, 2014)

loach guy said:


> You really should run your CO2 on separate systems. Personally, I would only have the outlet coming off the CO2 tank run to a manifold, and have separate regulators going off of that. That way each system is independent. What is good for one tank, may not be right for another.


That sounds like quite a complex/expensive/unnecessary setup. I've got individual needle valves running off of the manifold so I can fine tune each tank's needs. Still a young system, but seems to work well so far.


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## Malakian (Aug 23, 2014)

roadmaster said:


> I have read much about the topic in preparation for trying the gas and to become educated as to possible problems BEFORE they present themselves.
> As I understand it.pH controller regulates CO2 release which is directly related to the pH.
> Many things used in the tank or otherwise present, will have affect on the pH that affect's the amount of gas being released.
> Things like GH booster,Magnesium,phosphates,pH up or down product's,equillibrium,and or acids such as humic acids will influence the controller as the pH is also influenced NO?


Yes, the controller is of course affected by PH changes, it after all regulating it. But it is not affected by KH, and there is a direct correlation between co2 ppm and KH/PH which I'm pretty sure most know by now. So If I set my controller to say about 30ppm at 4KH, which would be about 6.6 ph. Now If you add, say humic acid the KH will fall say to 2 KH, depending on how much humic acid you add. Now the controller is still regulating the PH to 6.6, but with a KH of 2 you now have 16ppm of co2. To still be at 30ppm co2, you would need to reset you controller to a ph of 6.3 if you don't raise the KH again.



Bump: Hmm, I thought of something. Maybe our controllers don't work the same. Can you for example, tell the controller to drop the PH by 1 degree, no matter the starting PH? As in you tell it to drop your ph for 7 to 6, you then add something that makes the PH 6.5 and the controller would automatically drop it to 5.5 now. Mine works in the manner I use a dial to set the PH, when the Ph goes 0.2 degrees over that set point, the Co2 turns on and lowers the ph again to 0.1 under the set point.



natebuchholz said:


> ^ this is correct. It makes all of its decisions based upon a calibrated probe.


Bump2: So the controller doesn't regulate the co2 release, the regulator does that. The controller only adjusts the PH and when the Co2 is turned on and off, the speed (pressure) and amount (Needle valve opening) of gas coming out of the tube is the regulators job.


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## rick dale (Feb 26, 2014)

*pH controlle*

Milwaukee mc122. I would not inject co2 without one. Way better than a drop checker. I have never worried with what I have added to my tank , and have never had any problems , using my pH monitor. I set to a 1.0 pH drop . plants and fish are doing great ! Get one and you will be glad you did.


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## Malakian (Aug 23, 2014)

Found Tom Barr's comment on the matter, quoted from http://www.plantedtank.net/forums/showthread.php?t=91075

He explains what I mean. Its not a simple set and forget, sure way to do Co2. Thats all I wanted to inform about. As I have not had success with stable co2 in my tank using a controller. But it does seem to work for a lot of people.

"Really just a toy to fiddle with?

I can have 10000$ for a tank, and still find little use for it.

What does it honestly control?
pH or........CO2?

I'll contend it does control pH, if correctly set up, with enough flow through gph, decent mixing etc, calibration checks etc.

It does not however accurately control CO2. This is a function of flow rates, 3D structure within the aquarium, canopy formation of the plants, type of plants, both affectors of pH that are not CO2, affectors of KH that are not carbonate alkalinity, and tap changes in KH if those are not tested when doing water changes or KH drift.

A needle valve is like a simple thermostat.
A little more one way or the other adds more/less CO2.
They are stable and CO2 flow rates into the aquarium are the same once set.

This gets around KH issues, pH affectors etc. 

You still have to eyeball things, DC are not an end all either.
Both DC's and pH meters/controllers still are only one point in the aquarium, often the lower end of CO2 measure, there is variability in aquariums as far as CO2, more than I suspected/predicted.

Eyeballing things takes time and experience, something many do not do well or want to do. Like say NO3, they want to add 20ppm and then they know things are fine, however CO2 is far more complicated than that, many assume a pH controller makes all these issues go away, it does not however.

It may be used as a relative indicator of CO2, but the eyeballs should be used in conjunction with, but then it's really no better than the needle valve, which is arguably a much more stable and much simpler mechanical device to do this with. Or a pH meter, then use the valve to adjust from there.

I'd never install one on any system.
Yep, I've had them, played with them plenty.
Never will use them again.

CO2 controller perhaps(something that is not made(yet) and a lot of $$$), but even there, mostly just as a monitor, not a controller.

Regards, 
Tom Barr"


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## Kubla (Jan 5, 2014)

> A needle valve is like a simple thermostat.


I have to take exception to this statement and say a needle valve is nothing like a simple thermostat. That's just a horribly flawed analogy. A PH controller is much more like a simple thermostat. A thermostat has a sensor and turns something on or off depending on the sensor and the set point. That's what a PH controler does.
A needle valve is always on and controls the flow. It's just a valve after all.


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## Malakian (Aug 23, 2014)

Kubla said:


> I have to take exception to this statement and say a needle valve is nothing like a simple thermostat. That's just a horribly flawed analogy. A PH controller is much more like a simple thermostat. A thermostat has a sensor and turns something on or off depending on the sensor and the set point. That's what a PH controler does.
> A needle valve is always on and controls the flow. It's just a valve after all.


I do completely agree with that, but he overall describes the problem better than me.
But he may not know how a thermostat works properly, and just see the increase in temp as an analogy to increase in co2.


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## lee739 (Oct 12, 2014)

Malakian said:


> ......
> It does not however accurately control CO2. This is a function of flow rates, 3D structure within the aquarium, canopy formation of the plants, type of plants........
> .....
> Regards,
> Tom Barr"


If you ask me then any CO2 delivery system, unless you have an army of nanobots crawling your tank doing it, will have the same issues.....

I'll keep using my pH controller - you do need to get very intimate with your favourite KH test kit, and be aware of what is in your tank that affects its pH.
I wouldn't use coral sand anywhere, and care even with large pieces of wood that may affect pH. Know what your standard early morning, lights off, pH is, and be ready to make changes should it wander. Big water changes with constant water chemistry is the key IMO.....


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## Malakian (Aug 23, 2014)

True, but in my case with 0-1dKH water in the tap, can't get a accurate reading at so low concentrations. I pretty much have to add something to get the KH up, and with the water supply varying by season here in Norway as our main water supply freezes in the winter they switch to a local lake. So using a controller, when having so many variables to take into consideration seem to make a more imbalance than not, in my case at least.

And yes, all co2 systems have flaws. That is also what Tom is saying, not using a controller just eliminate drifting KH, non carbonate buffers etc. from the problem if you have/get one. Thats why are getting so wildly different results in seemingly same parameters. We don't have the technology available to the common man to in anyway effectively distribute co2 on a consistent set and forget method. But wouldn't you say 5ml pr hour co2 without controller, and an even 5 ml pr hour because of a stable KH with a controller is the same? At best in my eyes, its more of a work around in dialing in your regulator, and a fail-safe for over gassing. Not using the controller, and having a steady supply at least eliminates one variable to be off, and screwing with what you think is your ppm concentration of co2.

But again, to each his own. As I stated previously it seems to work for a lot of people, but it didn't for me and I believe this is the issue. And I have seen a lot of advocating a ph controller to be a safe, sure way to supply co2 lately. Would suck to spend a good amount of money for something that might not work in your case, so I just wanted to add some of the issues too with using a controller. Just my 2 cents.

Bump: and just to add, the probe is a high-end lab grade I got from the lab at my former work place, which I also performed controls on off-shore fluids. So I do know how important calibrating is and how to do it, and did so every week. So that wasn't the problem, so It had to be some KH related thing.


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## Culprit (Nov 6, 2012)

I have yet to find a controller/probe that stays calibrated past 8 days.


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## lee739 (Oct 12, 2014)

Culprit said:


> I have yet to find a controller/probe that stays calibrated past 8 days.


You need to look harder, mine wasn't very expensive - it holds calibration from one month to the next, the furthest off I've seen it so far (on a pH 7.00 standard), is 0.02 pH units..... good enough for government work!


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## Malakian (Aug 23, 2014)

lee739 said:


> You need to look harder, mine wasn't very expensive - it holds calibration from one month to the next, the furthest off I've seen it so far (on a pH 7.00 standard), is 0.02 pH units..... good enough for government work!


2nd this, the old probe ( was atleast 5 years old, and not stored properly for some time) would hold a calibration of about 1 week. And since we do dailiy calibrations at the lab, I am pretty used to it, so its just become a routine at WC for me. Though the new lab grade probe, have never been off since the day I got it. It is a 400$ probe, but you could get a very decent one for around 40-60$. This one is a lab grade for around 60$ Amazon.com: Bluelab pH Probe - Replacement pH Probe for Bluelab Meters, Monitors and Controllers - PROBPH: Industrial & Scientific

That was just a fast google search, and can probably find a better price. I myself use Mettler Toledo probe, but those start at around 150$.

Also the more expensive probes tend to be much faster at stabilizing, so if you have a 20$ probe. It may take up to 5 minutes for it to show correct ph, where as a lab grade takes usually under 30 sec. But that doesn't matter too much for our use.


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## larusaquarium (Feb 21, 2015)

Thanks for the info guys. After reading All the replies I have decided to go ahead and purchase one. Special thanks to rickdale and natebuchholz for explaining this in simple terms.


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