I too am just getting into the pressurized CO2 realm and found this thread incredibly
helpful in putting it all in perspective.
I already have my co2 tank and regulator; I just need to get a solenoid, bubble counter and needle valve. As helpful as that thread is, it's a bit dated. I'm trying to sort through which components are still available today.
That is my thread
It is also linked here on the TPT (see my signature below).
I try to update the parts from time to time - from what I know, the parts that I list in the article can still be used today.
Of course, between then and now, there have been many new additions that can be found, but I decided to only keep my article with the parts that can be found easily from retailers.
There are whole lists of what parts (i.e. needle valves) may work for our purposes, but again, either they are rare, or cost $200-300 (and I would assume most people do not want to spend that much).
Lets talk just regulators. Single stage vs. Dual stage, I am thinking dual stage but is it truely neccesary. Is the "end of tank dump" something to worry about. It seems from my research dual seems to be the right choice.
It all depends on your purpose.
EOTD is a phenomenon that can occur. However, if you take the precaution of always refilling your cylinder once the liquid CO2 has depleted (i.e. when the high pressure gauge begins to decrease), then you will have no problems with EOTD.
With a dual stage regulator, you can easily run the cylinder down to empty without any worries.
If so when looking on ebay I see a huge mind blowing selection of stuff. Are the beer ones (kegorator type) going to work well if I use a needle valve to really control flow? They seem inexpensive but that usually means cheap.
Those types of regulator will work fine, but they are single stage only.
They are less sturdy than the industrial regulators that people sometimes use (i.e. Victor, Concoa, etc).
Does it have to be a CO2 regulator or can say one that says Oxygen or someother gas be used.
Inert gas regulators are better. Regulators used for oxygen previously could have a bit more excessive wear and tear on the diaphragm, leading to potential DOA.
Pressures what should be the pressures, tank side and flow side?
For cylinder pressure, the high pressure side has to be capable of handling at least 1500 PSI (to be on the safe side). This is usually fine.
For the low pressure (delivery pressure) side, it depends on your purpose. For smaller aquariums, you may want something that has a finer resolution in the lower PSI range. Vice versa for larger aquariums.
It also depends on the type of diffuser you plan to use; some atomic type CO2 diffusers require higher pressures to operate (around 40 PSI), so you will have to take this into consideration when purchasing a regulator.