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CO2 Pressurized system queries

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I have a question about CO2. I am not very mechanically minded, but have CO2 as a pressurization system when spraying pesticides (I am a greenhouse worker). How does the PH monitor hook up to your CO2 system to regulate CO2 output?
Which system is better, the JBJ or Milwaukee for regulator? For PH monitor?
Now I am assuming the link provided
includes everything except a tank for the gas, the CO2 gas itself, and a PH regulator/monitor? Or is the PH monitor included? What's a good and not too pricey ph reg?
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The regulator's solenoid valve usually plugs into a controlled AC outlet on the pH controller.

As for what individual vendors include or don't include on a system, you should probably contact them directly to avoid any misunderstandings.
Where are good cheap places to get pressurized CO2 systems? What price range am I looking at for a system (basic, but with the PH regulator)? Are there any sites with good diagrams showing what part is what and what each part does, and how it fits together into a cohesive system?
Check out Marc at, he has great deals on combo systems.
You should check out all the sponsors (excluding me, closed for remodeling), ask questions of them and make an informed choice. said:
You should check out all the sponsors (excluding me, closed for remodeling), ask questions of them and make an informed choice.
Good point. There are all kinds of great sponsors/sources, and it doesn't hurt to check the different ones out to find the right system specifically for you.
I don't known how the system goes together, or the differences between the brands, well enough to make an informed decision.
Please keep in mind that part of this is my opinion, based on my experience and what I know of other's experiences then.

The minimum you need is a tank (I recommend 5 pound or larger), a regulator, bubble counter, needle valve and either a reactor or diffuser.

Either the Milwaukee MA957 or the JBJ will provide the reg., bubble counter and needle valve, and in reality the only real difference between the two models are the features and price. The Milwaukee doesn't have a check valve but has adjustable line pressure, the JBJ has a fixed line pressure but has a check valve. The need for a check valve is the topic of some discussion, as is fixed vs. adjustable line pressure, a check valve can be added to the Milwaukee for a very reasonable price and whether or not you want the line pressure to be adjustable is a matter of personal opinion more than anything.

The regulator hooks to the tank, the CO2 goes into the aquarium through the diffuser or reactor, either take care of disolving the CO2 into the water. Diffusers are more or less passive, simply bubbling CO2 into the tank, ideally in such a way as to maximze contact time with the water. Reactors are generally active, they release CO2 bubbles into a moving stream of water, usually through some kind of media that creates turbulence as well. As a rule they are more efficient than diffusers, but usually more expensive and a tad bit more difficult to set up.

I'm on my lunch so I have to quit typing, maybe someone else can take off from here, and of course correct anything I might be in error on.
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How does the PH monitor hook up to your CO2 system to regulate CO2 output?
The Milwaukee and JBJ assembled components include a solenoid valve, which is an electrically operated valve. These are usually in the closed position when electricity is off. (Called 'normally closed') Supply electricity to them and they open (via an electro-magnet) and allow the CO2 to pass through them. If you want CO during the photoperiod, plug the solenoid into the same timer as the lights. If you want CO2 24/7 then just plug them into the wall outlet, or really, just not include one in the system at all.

If you want to control the CO2 at all times then plug the solenoid into a controller, which is then plugged into the wall outlet. The controller switches the solenoid on and off in response to readings from a CO2 probe (which is also connected to the controller) placed in the tank water. While this sounds great in theory, it introduces a new set of problems that many have decided is not worth the trouble. Calibrating the probe being the primary source of errors. For general use aquariums, this level of control isn't needed, IMO.

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I disagree with the idea that a controller is too much trouble, but hey too each his own I guess. With the SMS122, you calibrate it for 7 and off ya go.

The only time I've heard of anyone having problems is when they try to make it too complicated and decide they need to calibrate it for 4, 7 and 10, which is contraindicated by the instructions.
I really like the controllers too.

I have them on all of my pressurized tanks and I'd never want to be without them anymore.
I've never had a problem with calibration, and if something goes haywire with the C02, the controller is going to shut it off before disaster strikes.

It isn't a necessity, but it sure is a luxury. :)
I have to admit I like mine as much for the gizmo factor as I do actual benefit.

But before I added controllers, I was getting about a 1 pH swing from light out to light on, my fish never seemed to suffer and I alleviated it somewhat by truning up the filter at night, but the controller has made it a lot simpler.
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