# [Wet Thumb Forum]-Co2 flowmeter Question



## wicked251 (Jan 19, 2005)

I am in the process of setting up a 55 gallon planted tank. I would like to get a flowmeter with needle valve for the Co2 system. My question is, what size of flowmeter in SCFM will I need. Any input would be great.

Thanks


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## wicked251 (Jan 19, 2005)

I am in the process of setting up a 55 gallon planted tank. I would like to get a flowmeter with needle valve for the Co2 system. My question is, what size of flowmeter in SCFM will I need. Any input would be great.

Thanks


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## Hawkeye (Aug 20, 2004)

Do you mean a bubble counter or an inline flowmeter to measure the amount volume of CO2 being moved thru the line?

Hawk


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## imported_Creature (Feb 6, 2003)

Just when I think I can't add any more technology to my aquarium set-up you guys come up with something else! I think the flowmeter you may be thinking about is called a direct read rotameter. I used to have one hooked up, but as I had "borrowed" it from work, I finally returned it and I'm just guessing at the moment. After some exhaustive searches I finally found a place with a great selection. http://www.omega.com/newsearchengine/esearch.asp?start=0&perPage=10&summary=yes&sort=rank&search=rotameters+CO2&submit=Search

Then I also saw the digital one, which is really cool and has the fittings already attached. While it's definitely not necessary, it would look really awesome, but at around $400, I'll have to settle for cool instead of awesome.


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## imported_Creature (Feb 6, 2003)

Here's the digital one.


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## wicked251 (Jan 19, 2005)

Thanks for the quick responces. I was looking at a Dwyer brand flowmeter( I cant Think of the model #). I am wanting to control the dosing of the co2 with the integrated needle valve.


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## Margolis (Sep 22, 2004)

It seems to me that since we are talking about having co2 rates in the bubble per minute range that a flow meter that reads in cubic feet per minute is going to be kind of useless.

Of course it could just be me


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## wicked251 (Jan 19, 2005)

I found that others online are using the Dwyer RMA-151-SSV. My mistake about the SCFM scale. The meter I am looking at is in CC/MIN. I was wondering if anyone on this forum has had any experience with a flowmeter versus a bubble counter. There are some pics at this link.http://www.reefs.org/library/article/needle_valve_alternatives.html


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## Robert Hudson (Feb 5, 2004)

But what is the point? What you should really be looking at is your pH and KH. That is the only way to accurately measure the C02 in your water. A bubble counter is just a quick easy visual check, and for those of us too lazy to check pH and KH, we take our chances and use it to estimate. These flow meters don't accomplish anything more than a bubble counter. You still need to test the water or you are shooting in the dark.


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## Margolis (Sep 22, 2004)

even cubic centimeters per minute is too large of an amount for this use. Unless you have a huge tank you probably won't even be pushing 1-2cc/min. The best way to go is to use a ph controller. I only use the bubble counter as visual confirmation that the thing is working.


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## wicked251 (Jan 19, 2005)

Thank you. That is exactly what I needed to know. Thanks again for the help.


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## imported_Creature (Feb 6, 2003)

I thought a bubble counter was used to fine tune the rate of CO2 addition, using the needle valve to increase or decrease the amount added to the reactor.

A pH controller is the best way to go. I don't need to use a bubble counter. The aqua medic I tried was a total waste of money, IMO.

Oh, couldn't a totalized volume of CO2 added during a given length of time give you an idea of how much plants are using, given that you account for normal diffusion to the air, a figure which could be obtained at night? Jast a passing thought on how else we might quantify plant growth on a daily basis.


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## imported_russell (Sep 14, 2004)

in my case especailly, i must account for loss of co2 through the surface of the tank.


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## imported_Creature (Feb 6, 2003)

Yeah, me too. I like a little ripple at the surface, which of course increases the surface area a the air-water interface. But, if you have a night time value of totalized CO2 volume used, you can use this to "zero" or to normalize your daytime totalized volume. One might even be able to track a diminished light output if a trend of CO2 "consumption" dimishes over time. Just an idea on how we might use a more quantitative analysis in determining plant mass production.


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