# pH controller V.S. constant CO2



## Stevie D (Jul 16, 2008)

You have to set your controller to the ph that gives you the required amount of co2. If you use a drop checker, adjust your ph until the drop checker is the color green you want. You can also measure the ph of a glass of water taken from your tank and let sit for 24 hours to degass all the co2. Then take a measurement and about a 1.0 drop in ph will give you about 30ppm of co2. 

The best thing about a controller is that when your lights are the brightest and the plants are using the most co2, the controller will always keep the optimal amount in the tank for the plants to use. When the plants use less, it will put less in the water. At night it will keep co2 in the tank, but i find that my solenoid hardly ever goes on when the lights are out, so it definitely uses less durning the night. 

The important thing is there is always enough co2 in the tank at all times with a controller, and this isn't proven, but i believe this does help against algae to those who shut their co2 off at night, as well as the flux you will get when the plants use more co2 than the constant supply of co2 is putting out. Now grated you won't have any algae problems if you have a balance tank no matter how you inject co2, but anything the helps, especially the beginner, can't hurt!



Stevie D


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## youareafever (Mar 18, 2008)

from what i understand pH is a poor measurement for co2 levels in ur tank.


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## unirdna (Jan 22, 2004)

Controllers were a very hot item a few years back, and many still do use them. But, I think that they are starting to fade - no longer considered a "mandatory" piece of a pressurized CO2 system. pH indicator solutions (drop checkers) and accumulation of knowledge is reducing the need for controllers more and more every year. 

I have used one in the past, but found that it was easier to simply dial in (needle valve) a constant bubble rate. The rate varies for each of my tanks, and is based on the pH/KH relationship, as well as observing my plants and fish. As mentioned, others use pH indicator solution and drop checkers. Saves $$ and there is one less piece of equipment that can malfunction.

That's how I see it. Others find them helpful.


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## die2win (Aug 10, 2008)

I've used a Ph controller from day one with Co2. And yes, once you have things "dialed in" with a drop checker, the controller seems to be overkill.

It is an insurance policy in my mind. I'm not going to have a disaster with Co2 as some have just recently here. The controller will cut the supply of Co2 off saving the tank and fish. Some of my fish are worth too much money and time invested to lose by an accident. 

Overkill? You have to decide what matters to you the most. :fish:


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## imeridian (Jan 19, 2007)

As the person recently having the CO2 disaster I'll say again that I doubt a pH controller would have helped. With the needle valve being bumped to nearly wide open, enough CO2 would have filled the reactor to be lethal before the pH would have dropped low enough for the controller to turn it off. 

I do agree, though, that a pH controller can work as an insurance policy against the more minor negligence mishaps; however provided only if the CO2 system is setup to function without the controller. 

Far too many seem to set the system so it is dependent on the controller, thus creating more risk with running the controller than they'd be at without... risk of pH controller malfunction, probe failure, or even water supply parameter changes. If the bubble rate of the CO2 is set to be capable of pumping more CO2 into the water than is safe without the controller, then the pH controller is a false sense of security and there is greater risk than not having a controller.


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## Discuss (Jul 13, 2008)

So How is the controller work? What should be set up at? is the controller preventing the ph to go down or up? I am new at this excuse my ignorance. thanks


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## imeridian (Jan 19, 2007)

With a standard one-setting pH controller you set it for the pH you want to maintain, it will provide power to your solenoid (in order to allow CO2 to flow) whenever the pH is higher than the set point. Once the pH reaches the set point it will turn off power to the solenoid.

The issue I mentioned previously is that some don't take the necessary care in setting their needle valve in order to work without the pH controller, thus if the CO2 were to run 'wide open' you can still gas the fish if there's an equipment malfunction or a water parameter change. 

For instance, if your water is typically a pH of 7 and you set the controller to 6, that's fine and dandy. What happens if your water supply changes, as some do, and your water is suddenly say a pH of 8? Your pH controller will run the CO2 indefinitely trying to get it down to 6. If you've taken the care to ensure that the bubble rate is such that when on constantly it'll be 30ppm, you're okay because the regulator settings physically prevent that dramatic of a change. If you've relied solely on the pH controller then you'll still have a tank of dead fish. 

If the water parameters shift the other way suddenly you're not providing enough CO2, that can happen regardless of how you have the bubble rate set. 

The same type of problem can happen if your pH probe becomes uncalibrated or otherwise begins to provide incorrect pH information. 

The same type of problem can happen if you have a change in pH from tannins or organic decomposition, basically any change in pH that isn't directly related to the water's KH.

This is why I'm basically against the pH controller, instead of having one thing to monitor, being the CO2 regulator / needle valve, you now have not only that, but the pH probe and water parameters too. There are now two more points of failure.


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## iporkgoats (Nov 19, 2008)

imeridian said:


> If you've taken the care to ensure that the bubble rate is such that when on constantly it'll be 30ppm, you're okay because the regulator settings physically prevent that dramatic of a change. If you've relied solely on the pH controller then you'll still have a tank of dead fish.


Are you suggesting that most likely someone using a pH controller does not take much consideration in the rate that the CO2 goes into the tank? (i am not stating that to bring on a debate about who puts that consideration into using their controller) I just want a better understanding. Let's say i have a drop checker and come to notice my pH controller reads 6.6 for the 30ppm. Couldn't that be beneficial? Or is that not how you use a drop checker along with a pH controller. I am not too clear, and understand the other factors that come into play, but i like the pH controller because i find my Milwaukee reg. sometimes does a bad job of regulating. I just took my tank to be refilled and i am struggling to get the bubbles consistant like i had previously.


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## imeridian (Jan 19, 2007)

I think it would behoove you to sell your controller in order to get a better regulator. I've had a Milwaukee, they're more costly in trouble than they ever save in money.

I'm saying that it has been very common that one doesn't dial in the bubble rate when using a controller. There have been plenty of stories of accidents with controllers because of that, solenoids sticking open come to mind also. 

A primary point I'm making is that, yes, if you're going to use a pH controller also be sure to dial in the CO2 bubble rate using either the ph/KH charts and/or a drop checker. Don't rely on the controller to prevent overdosing the CO2, use the needle valve to regulate the flow. If your regulator and needle valve are not adequate then you need better ones, not another gadget that introduces additional failure points.


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## Hoppy (Dec 24, 2005)

ashappar said:


> +1 to the posters mentioning regulators
> 
> a good regulator is all the peace of mind / insurance policy you need.
> I used pH controllers for years and got rid of them after I discovered good regulators.
> ...


Once you learn what bubble rate is appropriate for your tank I agree with you. The time when the tomfoolery is good is when you are learning what bubble rate you need, when you are new to CO2 and don't have any idea how to judge when you have enough or too much.

I use a Milwaukee regulator, and it does its job, but not well. Once I removed the bubble counter to get rid of that leak source it has been of acceptable quality. But, it can't handle a CO2 tank that is running out of CO2. The Milwaukee regulator output pressure goes up as the input pressure goes down - a recipe for disaster. If I felt I could afford it (meaning if I thought my wife wouldn't clobber me) I would definitely be shopping at Greenleaf for a new one.


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## Left C (Nov 15, 2003)

Should you decide to get a good quality regulator, May I suggest that you get a dual stage regulator made by Victor, Concoa, Matheson, etc? You can find used ones or even new ones on eBay at very good prices.

A dual stage regulator is really two regulators in one. The first stage adjusts the low pressure setting like a regular CO2 regulator. The second stage (that's the big hump on the back) controls the low pressure setting so that the pressure will never rise above your setting. You can run your CO2 cylinder until it is empty w/o fear of end of tank dump.

A good quality needle/metering valve like Fabco, Swagelok, Ideal, etc. will help too.



Left C said:


> How do you like your Victor dual stage regulator





fordtrannyman said:


> I love it!
> I have it set up with a DIY 3-way manifold using some cheap needle valves.
> When I first noticed the initial high side pressure drop from 900 to 600 psi, I kept a close eye on the low side-(Initial setting of 5psi). 3 days later 400 psi and the low side didn't budge. It wasn't until the tank was near empty (200 psi), that I had to adjust the low side to get every bit of C02 possible. This Regulator is not only very precise, but it got me another week of C02 and NO END OF TANK DUMP.


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## aquasox (Sep 3, 2005)

I have used a pH controller and without. I find setting to a constant bubble rate and leaving CO2 on 24/7 (without controller) works best....I can grow crypts much better and fish are happier. The pH controller is simply used as a pH monitor now. I would recommend a pH monitor though or perhaps a kH drop checker....but hell I even stopped buffering kH and pH has stabilized at slightly below 6...the simpler the better IMO


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## Stevie D (Jul 16, 2008)

If you use a ph controller you don't need a good regulator, or a good needle valve. So you will be fine as long as the controller is set correctly. Orcourse it's better if you do have a good regulator and needle valve ;-) Things do change, and it's important to monitor your drop checker. Also it's a good idea to change the solution in your drop checker every 2 weeks. 

For learning, i say you can't beat a controller. It's nice to always know your exact ph. If you make a mistake, you're covered. The fact is they don't fail all too often and you are definitely more likely to have an accident without a controller than with one. There is maintenance that is associated with a controller and it's probe, it's important that these are calibrated and replaced when needed. Other than that it's not such a bad thing that people are making them out to be. 

Knowing nothing about your water, if you use your drop checker to set your controller, you are not going to have a problem. This may need to be adjusted from time to time, but even then it's not often. It's really a matter of preference, but i think they have many benefits over not using them, and not the other way around like those who do not use them. Their are tradeoffs to using both. It's unfortunate that people brush off a controller like it is a bad thing these days. Like anything else in this hobby we strive to gain more control over the parameters and provide consistent conditions in our tanks. This is what a controller can do, but because it's expensive and you have to do maintenance it is almost "bad mouthed". You don't need a auto top off system or an automatic water change unit, but they are handy, and serve their purpose. For those who spend the money on units like these, they see it worth it for the convenience and reassurance that they will get done. It's the same type of thing when you are talking about a controller. Nothing bad there, just a choice.

Stevie D


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## captain_bu (Oct 20, 2007)

Stevie D said:


> Other than that it's not such a bad thing that people are making them out to be.
> 
> Stevie D


I don't think anyone is making them out to be a "bad thing" just unnecessary. Nothing wrong with using them if they give you peace of mind but you don't need one.


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## Left C (Nov 15, 2003)

I agree with Stevie D. I have 2 Milwaukee pH controllers and I just purchased a Pinpoint pH controller. I like them very much. They work with my dual stage regulators really well.

When I first got into pressurized CO2, the 4 dKH solution for the drop checkers wasn't around. I had two Azoo regulators. I found myself worrying about having too much CO2 that I was checking the pH frequently and even in the middle of the night. That was too worrisome for me. I got pH controllers after that and I have had no problems with them. I do my maintenance with the probes and I keep backups in case that I need them. 

I've had only one problem with pressurized CO2 since I started. I had just set up a new AP.com "The Best" regulator which is called the "Second Best" regulator now. The solenoid stuck open and killed my fish during the night. It was not the pH controller's fault. I sent it back to AP.com and they told me that they found a piece of Teflon stuck in the solenoid which kept it from closing all the way. It happened when they built the regulator.

For my use and piece of mind, I like pH controllers, 4 dKH drop checkers and dual stage regulators with good quality metering valves.


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