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So obviously this doesn't come with a needle valve, but that can always be added. But seriously, what if one could win this for the minimum .99 cent bid. The only part that is risky is having to pay 15 bucks shipping for a potential useless item. Could this be that bad that it isn't worth it. I see it actually selling across e-bay for like 70 bucks for a "buy it now" price.

http://cgi.e-bay.com/ws/eBayISAPI.d... (remove the hyphen in e-bay to use the link)
 

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Very interesting. Now that I think about it how many cubic feet per hour are we making? .5cu ft. an hour really sounds like nothing when I think about it. Maybe 1bps in our terms.
 

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It isn't a good buy. The flow rates that the valve will handle are much too high for aquarium use. The flow meter is useless for 2 bbs flow rate. The regulator might work, but I doubt it, leaving you with only a possibly useful solenoid valve. But, if you can actually get it for $5, that might be a good deal on a solenoid.
 

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Very interesting. Now that I think about it how many cubic feet per hour are we making? .5cu ft. an hour really sounds like nothing when I think about it. Maybe 1bps in our terms.
I went ahead and used a calculator to try and figure this out. Obviously it is inherently hard to determine the space of a bubble so I used one drop instead. (1ml=20 drops). With that information there is 283,168 drops per .5 cubic feet. Divide that by 60 to get "drops" per minute and you get 4719, divide again to get drops per second and you get roughly 78. Pretty damn high I think. Again, these are all real loose figures, but why couldn't this work on a tank with a pH controller? As long as that solenoid actually works then no reason why you can't use it with a controller.
 

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I looked at trying to use a flowmeter for a while. I think my best estimate for a meaningful range was 0-.1 sccm (standard cubic cm per minute), such flowmeters do exist, and the >$1000 prices on them explains why we use bubble counters. :smile:
 

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I went ahead and used a calculator to try and figure this out. Obviously it is inherently hard to determine the space of a bubble so I used one drop instead. (1ml=20 drops). With that information there is 283,168 drops per .5 cubic feet. Divide that by 60 to get "drops" per minute and you get 4719, divide again to get drops per second and you get roughly 78. Pretty damn high I think. Again, these are all real loose figures, but why couldn't this work on a tank with a pH controller? As long as that solenoid actually works then no reason why you can't use it with a controller.

Really? My bubbles are closer to maybe .5ml each..... I figured this out since I used a 1ml syringe as part of my bubble counter.
 

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A .5ml bubble would be nearly 1cm (91mm, to be precise) across. This causes me to wonder if your volume estimate might be a trifle ... generous?

The bubbles definitely span more than 1/20th of a ml. I would ballpark them anywhere from .5-.1 in size. It's not very consistent. Sometimes I get big gobbing bubbles as well.

edit: On second thought a cubic foot is bigger than I expected...they really need to put things in metric for me :D

But I think we would only need a flow valve that's maybe more precise between 100ml-1L ranges nothing extreme like 1ml.
 

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it works as a preset output pressure single stage regulator. you need to add a needle/metering valve after the solenoid for the flow rate we need, and completely ignore the build in flow meter.
I don't know what is the preset output pressure of this regulator, it may be too low or too high, need to find that out also.


don't recommend it because this regulator has small diaphragm and the output pressure rise is too high, may cause large excess amount of co2 injection when input pressure drop.

add the picture for clear viewing.
 

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But I think we would only need a flow valve that's maybe more precise between 100ml-1L ranges nothing extreme like 1ml.
100ml per minute would be 6 liters per hour. That's an awful lot of gas. A pound of CO2 is 231 liters, so a 10lb tank would run out in 385 hours, or just over 16 days if running 24 hour a day.

Somehow, I just don't think a 100ml/minute flowmeter will do. :smile:
 

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For additional reference, I have a seltzer bottle that carbonates (as in makes fizzy) 1.5 liters of water with a cartridge containing just 10ml of CO2.

Unless, of course, you're talking about a really big aquarium ....
 

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100ml per minute would be 6 liters per hour. That's an awful lot of gas. A pound of CO2 is 231 liters, so a 10lb tank would run out in 385 hours, or just over 16 days if running 24 hour a day.

Somehow, I just don't think a 100ml/minute flowmeter will do. :smile:
That doesn't sound quite right. What temperature and pressure? A 10lb tank contains appx. 2537L of gaseous CO2(At 1atm and 300K)...if I did my math right. It contains ~6L liquid.

Edit: my bad misread your post haha. Hmm...Interesting

Oh you said minute. I thought you meant 100ml an hour. That flow meter was .5 cu ft an hour so I assumed that's what we were going by. Even then...that's only about 3 months. On a 90+ gallon tank that's actually pretty reasonable...
I think 1-100ml is the number we're looking for. Oh well I better get some sleep now my reading and typing skills are starting to fall apart.
From the ebay:
The flow rate is adjustable from .5 - 15 Cubic Feet Per Hour.
 

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1 cubic foot is ~28 liters, so that's 14-420 liters/hour, which means (using my lower 231 liters/lb) a 10lb tank would empty in 5.5-165 hours (~6.9 days) of continuous use.

Still seems kinda fast ....
 
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