What size tubing for CO2? - The Planted Tank Forum
 
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post #1 of 10 (permalink) Old 11-15-2012, 07:31 PM Thread Starter
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What size tubing for CO2?

First off, hello all. This is my first post though I've been lurking for quite while.

I recently decided to try my hand at a CO2 set-up, mostly because I jumped the gun and threw too much light over my tank(4X39W T5HO over a 45G)and I ran into some algae problems.

Here is my question, I picked up a cheap swagelok needle valve(B-OVM2-BKB) on ebay thinking I got a great deal. Turns out it's an average needle valve but I'm going to give it a shot. When I googled the part number I came across a post on a forum referencing the exact valve and saying I needed a couple parts to make it work. Those parts were a 1/8 inch coupler and a 1/8 MIP to 1/4inch compression elbow to allow me to attach the tubing to the valve.

Now I've got everything put together, made myself a Rex Grigg's style reactor, and am about ready to go. Though it occurred to me that most bubble counters may require something smaller than 1/4 inch ID tubing.

Is this the case and I found bad information saying to get the 1/4 inch compression fitting? Or are you able to attach a bubble counter to this size tube? Do people use 1/4"ID tubing for CO2 and if so what do they use for bubble counters?

Worst case I can head to Lowes and find a 1/8MIP to 1/8 compression elbow and return the 1/4"ID tube for 1/8"ID. I'm just glad I thought about this before drilling out the hole for the tubing in the reactor.

Thanks in advance!
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post #2 of 10 (permalink) Old 11-15-2012, 09:15 PM
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1/4" compression is 1/4" od which is what you want. You will need a swagelok tube insert and 1/4 od 1/8 id tubing.
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post #3 of 10 (permalink) Old 11-15-2012, 09:32 PM Thread Starter
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Quote:
Originally Posted by ianiwane View Post
1/4" compression is 1/4" od which is what you want. You will need a swagelok tube insert and 1/4 od 1/8 id tubing.
Great, thank you.

So this may all just be due to my ignorance on the subject after all. The piece I got was 1/4" compression which I took to mean "fits 1/4 inch ID tubing", but from what you're saying it means "fits 1/4 inch OD tubing".

I hadn't actually tried to fit the tubing yet to see as the thought just occurred to me this morning while shopping for a bubble counter. Hopefully the advice I had initially found was correct. Either way, glad I asked before drilling that hole for the CO2 tube.

Thanks for your prompt reply.
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post #4 of 10 (permalink) Old 11-15-2012, 10:41 PM
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I hate to be the bearer of bad news. When going with Swagelok for a needle valve selection, you need to go with their metering valves. Their needle valves are much too coarse (their Cv is much too high) for our use. When you first crack them open, they are going much too fast. They are basically only on/off valves then. When looking for Swagelok, go with their low flow metering valves. Some of their medium flow metering valves will work for our use too. Swagelok's high flow metering valves will not work. They are too coarse as well.

B-OVM2 without the BKB handle: http://swagelok.com/search/find_prod...t=B-OVM2&item=
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post #5 of 10 (permalink) Old 11-15-2012, 11:43 PM Thread Starter
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No worries, I kind of figured it may not work well. Originally I was just going to do a cheap paintball set up without a regulator and I kept reading that the cheap Watts valves were only rated at 400psi and were an accident waiting to happen. That's part of the reason i picked this one. After I already got the valve I decided to stay the PB tank route but use a real regulator instead of an on/off valve. Until my budget refreshes next month I'll just have to play around with this one.

You linked to the B-OVM2, is that just to show one like mine that wouldn't work well? Also, is the only difference between what I got and that one the handle?

Also, I checked and it was the correct fitting for the valve, just my misunderstanding on what the 1/4" was referencing.

Thanks!
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post #6 of 10 (permalink) Old 11-16-2012, 01:05 AM
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Quote:
Originally Posted by parker679 View Post
No worries, I kind of figured it may not work well. Originally I was just going to do a cheap paintball set up without a regulator and I kept reading that the cheap Watts valves were only rated at 400psi and were an accident waiting to happen. That's part of the reason i picked this one. After I already got the valve I decided to stay the PB tank route but use a real regulator instead of an on/off valve. Until my budget refreshes next month I'll just have to play around with this one.
I surely understand about waiting until my cash replenishes on the next month. It is how I had to purchase my CO2 stuff. A regulator one month. A CO2 cylinder the next. A solenoid the next and so on. It sucked doing it this way, but I was able to get what I wanted. I ended up with a nice one (I thought so anyway.) for my first build.

Quote:
Originally Posted by parker679 View Post
You linked to the B-OVM2, is that just to show one like mine that wouldn't work well? Also, is the only difference between what I got and that one the handle?
It is just like your valve except the handle is difference. I gave you the link that has its specs so that you could review them. Here is the information about Swagelok's metering valves. This may help you when looking for them.

Quote:
Originally Posted by parker679 View Post
Also, I checked and it was the correct fitting for the valve, just my misunderstanding on what the 1/4" was referencing.

Thanks!
According to Swagelok's nomenclature, the number "2" in the part number means that it is a 1/8" part. If there was a "4" in the part number, it would indicate a 1/4" product.
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post #7 of 10 (permalink) Old 11-16-2012, 01:24 AM
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What you describe you have in the first post is the needle valve (which I'm going to guess should be useable based on its Cv, just not great) with 1/8" MNPT ports, then you've got a coupling, which I assume is 1/8" FNPT to 1/8" FNPT, then a 1/8" MNPT to 1/4" compression elbow. If all this is correct (and you actually have all these parts - I wasn't sure, based on your first post, if you'd already gotten them), then you're all set, *except* for the tubing insert that ianiwane mentioned.

The compression fitting you're talking about is the correct size. But if you have a Home Depot product, the compression elbow comes with everything you need. If you have a Swagelok/Parker/Bi-lok etc. part, with two ferrules inside the nut on that fitting, you still need the aforementioned insert, specifically sized for 1/4 - 1/8 tubing. Any specifically-sized insert will do (you don't need a Swagelok part for a Swagelok compression fitting - all those double-ferrule-type compression fittings are identical in function).

A picture of the parts will help.

By the way, MNPT = Male NPT = MIP. In the hobby, you'll usually see that thread standard referenced as the first two, rather than the third.
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post #8 of 10 (permalink) Old 11-16-2012, 03:42 AM Thread Starter
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Kevmo911: Thanks for the update on the nomenclature. You are correct, I have already purchased those pieces from amazon and the compression elbow did come with the insert for the tube as well as the ferrule which is attached to the compression nut.

At first I was just going to use an ASA on/off type valve on the tank which doesn't regulate the pressure. I was using Jaggedfury's write up as my guide. I saw there was some concern from people that having the full pressure of the tank on the needle valve was an accident waiting to happen so I opted to get a regulator instead though I had already purchased the higher psi needle valve.

I don't have my camera handy but below are pictures(from amazon and ebay auctions) of the items I got.

This is the needle valve.



This is the compression elbow. I'm not posting the coupling as I'm sure you all know what a 1/8" FNPT coupling looks like. This picture doesn't show it but it came with what I assume is the insert. A hollow tube that is flared at one end and fits inside standard airline tubing.



This is the regulator I got. It's a used single stage Taprite. I know it's not top of the line but for $16 it works for my entry into CO2.



Also, I know it's off topic but I was hoping for an opinion on this regulator. I got it fpr $10. It looks like it's dual stage but I'm not 100%. It's a used Union Carbide, I know it will need a CGA 320 nipple and nut but for the price I figured I could buy one for relatively cheap to make it work with CO2. Will it be a problem that the high side gauge goes up to 4000?




Thanks for the help guys. I've kept fish for years but am new to CO2 and planted tanks. As much as I hate to ask for help(I prefer to teach myself) I had to accept that it may be easier for me to ask questions of people who know much more than I do.
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post #9 of 10 (permalink) Old 11-16-2012, 03:55 AM
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Not sure that compression fitting looks quite right. It's hard to tell, as I'm used to seeing the double-ferrule compression fittings, but the thread diameter on the 1/4" tube side looks a bit small. Normally they'd be about the same diameter as the 1/8" NPT side (though completely different thread count).

But, again, I'm not familiar with that type of fitting. As long as the opening in the nut is 1/4", and the diameter of the 1/8" NPT threads (on the other side) is a bit under half an inch (0.4"), you're golden.

As for that second reg, I'd also be interested to know if it's a dual stage. No worries on the gauges, and output range is perfect. As long as it works (and you can get that CGA nipple off), it should be fine. If you can flip it around and get a pic, we could probably give you a better idea if it's a dual. A model number *might* help, but I have a feeling it's so old there might not even be any info on it on the 'net
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post #10 of 10 (permalink) Old 11-16-2012, 04:13 AM Thread Starter
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Quote:
Originally Posted by kevmo911 View Post
Not sure that compression fitting looks quite right. It's hard to tell, as I'm used to seeing the double-ferrule compression fittings, but the thread diameter on the 1/4" tube side looks a bit small. Normally they'd be about the same diameter as the 1/8" NPT side (though completely different thread count).

But, again, I'm not familiar with that type of fitting. As long as the opening in the nut is 1/4", and the diameter of the 1/8" NPT threads (on the other side) is a bit under half an inch (0.4"), you're golden.

As for that second reg, I'd also be interested to know if it's a dual stage. No worries on the gauges, and output range is perfect. As long as it works (and you can get that CGA nipple off), it should be fine. If you can flip it around and get a pic, we could probably give you a better idea if it's a dual. A model number *might* help, but I have a feeling it's so old there might not even be any info on it on the 'net
The non compression side of the elbow I'm sure is correct as I had no problem getting it attached to the needle valve via the coupling.

As for the compression, I can slide the air line tubing I have into the ferrule though it's a bit tight and once it's in the insert doesn't easily slide into the tube. Though I just grabbed some scrap tubing I had and am not 100% sure as to the size. Ok, decided to grab my digital calipers to see for sure. Inside diameter of the ferrule is .25" and the insert is .125" OD, everything checks out.

Regarding the Union Carbide reg, that's the pic from the auction, I should be getting it in the mail tomorrow and will know for sure. The auction didn't say if it was single or double stage, I just saw that portion below the high pressure gauge and it looked like the pictures I've seen of double stage regs.

The auction listing says it's a "Union Carbide Purox R-2052 Gas Regulator".
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