Diy Pressurized Co2?

[SkiFletch]

Hey all, new to this whole planted scene of the forums and the fishkeeping scene in general with some basic questions about CO2. I've read through all the stickies here which were exceptionally helpful and I'm pretty sure the planted route is for me. One interesting aspect about the planted scene I noticed right off the bat was CO2 addition (also fertilization) to the water to aid growth in photosynthesis. I knew all those biochem classes back in college would come in useful someday

Anyways, as soon as I heard CO2, I thought about compressed CO2 and my experiences with it through work (I'm a Technician in a hyperbarics lab) and through paintball. It seems to me that I'd easily be able to setup my own CO2 system with parts I have on hand from old markers (paintball guns) and needle valves. If what I understand is correct all I'll need parts wise are:

CO2 Bottle (got a 20oz)
Regulator (have a 2-stage)
Check Valve (got that)
Flow control valve (plent of those)
Misc fittings (wow have we got those at work )
CO2 Proof tubing (might have this...?)
Diffuser (gotta figure that out)

As I understand it I'll want to affix my regulator to my bottle, the check valve to the regulator, the flow control valve to the check valve and then the diffuser into the water on the end of the supply tube which is CO2 proof. I've got years of experience using compressed gas at work so this kind of thing is old-hat to me. My two questions lie in the CO2 proof tubing and the diffuser.

First, when you all say CO2 proof tubing are you simply referring to tubes that will not be effected by the freezing that is sometimes associated with expanding liquid CO2? What exactly is this tubing made of? Stainles steel? Copper? Brass? Nylon? Polyethelyne? Other? We usually use stainless steel tubing for our CO2 endeavors but I'm just curious if theres something special going on here in an aquarium that I dont know about.

Second question is regarding the diffuser. I understand the concept of a diffuser in that it maintains the CO2 bubble's contact with water for longer and thus allowing more CO2 to diffuse into the water, but how are they constructed? Is it kind of like a thin back and forth ladder with some pinholes here and there to allow water in behind successive bubbles? Are there other simpler methods that can be designed? I'd read about the overturned glass jar method and was debating a similar approach using part of my decorations as I want to try and keep the diffuser hidden if possible and dont have a lot of under the tank space. I was thinking of running my regulated lines under my substrate and allowing them to pop up and bubble into my sunken pirate ship fixture (cheesy, I know) to be held there for diffusion. Would this method work? Or shoudl I think along different lines.

Please keep in mind that I'd like to build things as much as possible myself for 2 reasons: cost, and I like working with my hands to make things. I have access to a full machine shop with the experience to utilize it all, materials galore, and probably most tools you can think of so if theres an outside the box way to make a good diffuser with machining please let me know.

Thanks for reading my disertation here and offering your help, its always appreciated

 

[donkey]

Hi
everything you need to know about CO2 can be found here
http/www.qsl.net/w2wdx/aquaria/diyco2.html

theres stuff on how to make a Diffuser .a lot of people like me just use the silicon type of air line and it seems to work fine i myself went with a DIY compressed CO2 but instead of using the paint ball stuff i got hold of a pub CO2 bottle . it holds about 18 pound of CO2 so it will last forever and it only costs about £5 to £10 to fill it back up .i got the Regulator from Ebay for a £10 and i got a Flow control valve from BOC .the whole thing cost me about £25 .and it works great . i am not sure if your in the U.K but the pub CO2 bottles are easy to get hold of .

 

[donkey]

i found a few more links for ya .they might be worth a look at

http/aquabotanicwetthumb.infopop.cc/eve/...12/m/1276009343

http/www.csd.net/~cgadd/aqua/diy_co2rig.htm

http/www.thekrib.com/Plants/CO2/

 

[sif]

Donkey what regulator did you get?

 

[zig]

Im not to sure what the co2 proof hosing is made of, but basically the reason we use it is because ordinary hosing used in aquariums will leak co2, most types of hosing are permeable by co2 and you will suffer co2 loss usually up to 20% depending on the type of tubing you use, im sure if you do a bit of research you can find what co2 proof hosing is made of.

The simplist diffuser you can have is the impellor on your filter, run the hosing releasing the co2 bubbles into your filiter and the impellor will do the rest, it will chop the bubbes into a very fine mist that will dissolve upon entry back into the water.

There are many variations on diffusers, if you have an external cannister filter you can make a homemade reactor out of easy to find plumbing parts, these type of diffusers are probably the most efficient they also run inline with the filter which keeps the diffuser out of the tank.

More simple although also very efficient diffusers are ladder type diffusers, this type of diffuser would go inside the tank.

There are a multitude of designs available for external reactors a google search will throw up loads of different types although they all basically do the same job and function very similarily.

The ladder type reactors are as you describe, the co2 bubble will dissolve as it travels up the ladder getting smaller as it does.


Ladder diffuser

The only thing you need to worry about with the DIY co2 system is that the needle valve will reduce the supply of co2 to a trickle, the needle valve needs to be able to be very fine tuned to reduce the flow of the co2.

 

[Lateral Line]

>>> sure what the co2 proof hosing is made of

Silicone.

 

[SkiFletch]

Thanks for all the replied guys, that was real helpful. As for the tubing that makes sense since certain plastics are gas semi permeable. I'd probably be using stainless steel tubing which I know isn't gas permeable

As for the diffuser, I use an overhang filter since my tank is pretty small. Would adding CO2 into the impeller there be a viable option, or is that more of an option for canister filters?

As for the needle valve I'm not worried about that at all. When you work in a hyperbarics lab there's a lot of really expensive good quality needle valves to go around . Plus I'll regulate the CO2 down to 1 PSI over depth or less which even the most basic needle valves could account for.

Still ruminating about the diffuser but it looks like I have some good ideas so far. Oh, and as for filling the bottle, thats not a problem when you have a 20 foot long tank full of CO2

 

[donkey]

@ sif
i got it from ebay it had two clocks on it one to tell me how much is in the bottle and the other to tell me the pressure .i got it for £10 .but there is a bloke on ebay that sells pub bottle Regulator but they dont have any clocks on them .he sells them all the time i could find his name out for ya if you need it .if your in to DIY then you could find a way to rig this up . been honest i dont think you really need the clocks on the Regulator . as its a 18 pound bottle i never look at it to see how much is left in it

you can also get them from B.O.C . but i dont know how much they cost .but it will cost u a lot less than buying a co2 system from a pet shop .they only come with a little bottle and you would be forever filling it up. this will last me for years

 

[sif]

@ sif
i got it from ebay it had two clocks on it one to tell me how much is in the bottle and the other to tell me the pressure .i got it for £10 .but there is a bloke on ebay that sells pub bottle Regulator but they dont have any clocks on them .he sells them all the time i could find his name out for ya if you need it .if your in to DIY then you could find a way to rig this up . been honest i dont think you really need the clocks on the Regulator . as its a 18 pound bottle i never look at it to see how much is left in it

you can also get them from B.O.C . but i dont know how much they cost .but it will cost u a lot less than buying a co2 system from a pet shop .they only come with a little bottle and you would be forever filling it up. this will last me for years

Cheers I'll have a look on EBAY. I'm guessing the pub bottle was from your local friendly gas supplier? Got that Ebay RO unit by the way so I'm getting there...

 

[donkey]

glad to hear it sif .just run it for 24 hours before you start to collect the water . i got the CO2 bottle from a pub .my mate works in . they have loads of them round the back so he got me one .so if you know someone who has a pub or a club they might give you one .but to be honest i dont think there worth much as i see them all over the place just sitting there :hey .if you do get hold of one just make sure its not a B.O.C one as you will have problems getting it filled

 

[donkey]

forgot to say .make sure you add something to the RO water like . KENT RO or Seachem Equilibrium or Electro-right . or just cut it with some tap water .as fish cant live in pure RO water