Regulator explanations: gauges, solenoid, etc.

[anathema]

I am trying to understand what all the extra are for on calcium reactor CO2 setups.

Why do I need two gauges?

What do the gauges measure?

If I have two gauges, do i need a bubble counter?

If I have a bubble counter, do i need two gauges?

Is a solenoid REALLY neccesary, ie; how long of a power outage would it take to cause a real problem?

Thanks!

[barebottoms]

Why do I need two gauges?

High pressure -> Medium pressure -> Low Pressure. A single regulator (single guage) can not handle the grandularity needed from the very high pressure of the tank to the very low requirements of a CA reactor.

What do the gauges measure?

Pressure

If I have two gauges, do i need a bubble counter?

Sort of? Everyone in Aquaria talks in BPM, so that is the standard reference. From my observastion, I can't see any correlation between PSI to BPM, my regulator gauge indicates its very low at the second stage of the regulator already. So I don't think its going to be precise enough.

If I have a bubble counter, do i need two gauges?

Yes, see the explanation of the 2 "guages"

Is a solenoid REALLY neccesary, ie; how long of a power outage would it take to cause a real problem?

Depends on what you run your "bubble count at", how safe you want to be, total water volume. If you have a lets say 20 gallon tank, then the amount of CO2 that will be needed to saturate your water volume will be very low, so a solenoid will be a good choice. But if you have a monster tank and you run your output at 60 bpm then the amount of CO2 going into the system to change the ph has to be very high. So how long the power outage is will dictate if you want to chance the ph swing.

Because remember a power outage will cut off the recirculation pump, the C02 will go through the reactor much faster now.

[anathema]

but I still don't understand.

I need to measure how much CO2 is left in the tank(high pressure), but why do i need to measure low pressure if I am counting bubbles? What does that reading give me in information that a single reading of the overall tank pressure coupled with a bubble count doesn't?

ie; if I have gauge A, measuring high pressure to show the co2 remaining in the cannister, and gauge B, showing the low pressure to show how much gas I am sending through the bubble counter, which is C, and the bubble counter is what I really get a measurement from anyway.

That pretty much makes gauge B a useless expense.

Considering I can pick up a regulator for $14.99 with a single gauge and pair it with a bubble counter, what am I missing here? Why should I spend $100 or is this another example of aquarium specific metal halide lighting?

[barebottoms]

I think the mix up is the "guage". In actuality, the guage is attached to a regulator. The regulator is rated for a certain pressure before the diaphram blows.

As I under stand it, its not possible to make a regulator that can go from 180 psi all the way down to 2 PSI. Made up numbers, since I don't remember.

So a dual "guage" regulator really has 2 regulators in it. one that goes from 180 down to 60 psi, then the second regulator goes from 60 to 2 psi. Made up numbers again, but thats what a 2 "guage" regulator is doing.

As for overprice aquaria equipment. I think you're right. You can get the 2 (high and low) regulators you need from a welding supply shop. Then get a precision needle valve to go to the bubble counter. All for a lot less than the aquaria setup.

It will end up being bulkier, but a lot more precise too. I'll look up the exact ratings if you need it and the next time I go down to the basement.

As to why the gauge because you have the bubble counter, really it doesn't matter that much, as long as your final output from the C02 tank is not at such a high pressure that it will blow the CA Reactor. Again, as I understand it it takes 2 steps via regulators to get there.

Also you can make a bubble counter with an old salifert test cup easily enough.


Edit:

I was wrong. You were right that its the Guages that aquaria tries to sell you on. There is only 1 regulator. The 2 guages is better control and more presise readings of the low pressure psi.

But everything else applies. Just as long as you have pressure output lower than what will blow your CA reactor, and a precise needle valve to control you BPM, you're set.

[jdieck]

First a regulator regulates pressure not flow.
Second. CO2 content in the tank can not be meassured with a pressure gauge as at the operating pressure in the cylinder the CO2 is liquid, meaning an almost constant pressure (Changes with ambient temperature) troughout the consumption.
If you want to know the content you need to weight the cylinder.

Why do you need two gauges and a bubble counter.
Gauge one meassures the pressure in the cylinder, in other words FULL (850 to 1100 psi) or empty Below 850 and dropping fast after that.
This gauge also helps you troubleshoot and detect potential overfilling.

The most useful regulators are the ones that alow you to adjust the ouput pressure. For a fixed orifice the pressure is almost proportional to the flow for a given range. So assuming you have a fixed aperture in the needle valve the higher the regulator output pressure the higher the flow and viceversa. On the other hand a regulator maintains the outlet pressure constant so when you change the setting of the needle valve (larger or smaller aperture the regulator compensate and cuts down the passage of product so as to maintain the otput pressure constant.

In other wordsw by adjusting the output pressure (For which you need the second gauge) and the needle valve you can obtain a more precise and stable bubble rate.
For our purpose and such small flows you want to keep as low a pressure as the regulator can "regulate" usually 10 to 15 psi in the output so the needle valve is less sensitive so larger changes in "orifice" (aperture) can create more reasonable changes in bubble rate. If your output pressure is too high any minute touch of the valve knob will significantly change your rate. Here is were the second gauge is useful.

At the end it is the combination of output pressure gauge, needle valve and bubble counter what helps you turn pressure into stable flow.

It is also useful to troubleshoot. As an example, if you are not getting flow how would you know if your needle valve is plugged or the regulator is not opening unless you have a gauge that tells you there is pressure at the entrance of the needle valve.

The ouput gauge serves also to prevent overpresurization of the system. Say you have a reactor designed for a maximum of 25 psy (I have seen some burst below this range) If your output pressure is set say at 45 psi and you do not know it if your reactor gets plugged or close the feed and driplines even at bubble rates the reactor pressure will eventually rise to the 45 psi with dangerous consequences as our reactors do not have a safety valve or bursting disk to prevent a blowup.

As for the Solenoid, I you are not going to use a controller you most probably do not need it unless there is a power failure to cut the CO2 supply. With a PH controller the solenoid is a must. You can close the CO2 supply when your effluent PH is below the set point and open it again if it is above that set point. In addition is you have an aquarium controller (Octopus, Neptune, YSI etc.) you can shut the CO2 if your tank PH drops too much regardless of what the PH controller is set at.

BTW Did you really found a regulator for $14.99 I will be interested to know more about it. There are material compatibility, pressure ratings, flow characteristics, DOT and CGA regulations and registrations and so issues you need to consider. I have seen too many injured people and property damage by a blown regulator to be doubtful enough. By the way, a non certified out of code unit may invalidate your insurance.

Hope I help with your questions...
Regards and Good Luck.

[kgross]

Single gauge verses dual gauge. ONce the reactor is setup and running there is no difference. On my setups I have single gauge regulators on every one.

Bubble counter. Yes you need one or a very low flow flow meter. You will also need a needle valve to adjust the flow slow enough for your needs.

Solenoid it is not needed, only problem is if you have a long power outage you could vapor lock your reactor depending on how it is setup.

As for what each item does, the regulator decreases the pressure from the tank, which is pretty high, to a lower pressure that is easier to work with. Once you drop the pressure down below 20 psi or so you can use normal airline tubing if you want to, at high pressures you will have to use all high pressure hose and if you have a problem (leak) your tank will empty a lot faster. If your regulator has 2 gauges it will display how much pressure is in your tank and how much you have in your line a single pressure regulator does not tell you how much pressure is in the tank.

Needle valve, this is just a very precise low flow valve that you use to adjust the actual flow of co/2, to measure the flow you use the bubble counter which allows you to count the number of bubbles of co/2 used per minute.

I hope this helps.

Kim

[anathema]

Hmmm, well yikes, here is what i get for playing around on Ebay:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2542598351&ssPageName=ADME:B:BN:US:1

Yes, uninked is me...

So I guess I am now the proud owner of what I hope is a useful setup. I don't see anything wrong with it barring possible cylinder contamination.

Run a search on CO2 regulators on Ebay, there are a ton for 19.99 buy it now and several under.

The one I ended up with appears to be good quality, I guess I will see when I get it.

[anathema]

What do you guys think, good deal or not? Just finished paying for it, $87 shipped which seem to be about the price of a regulator in most places.

[kgross]

That is a pretty good price. Now all you need is a needle valve and a bubble counter and you are all set.

Kim

[jdieck]

It looks like a 20 pund capacity cylinder typical for beberage applications.

If new it is a super excellent deal. The cylinder alone will cost you more than what you paid for. If used insure that the filler fully inspects it for you and that the hydrotest is not due.

The rgulator is very generic but you shall have no problem adapting it for your use. (Need to add the cost of a bubbler).

Good Luck.

[anathema]

Thanks for the help everyone.

Can you point me to a good needle valve & bubbler?

Now I am all set for the local club's DIY meeting this month.

[jdieck]

http://www.premiumaquatics.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=PA&Category_Code=cparts

Good Luck!