|
|
DIY CO2 System
This page shows how to put together your own CO2 system, using a pressurized CO2 tank,
regulator, and needle-valve. I don't discuss the yeast method here, but there are
many other sites out there that do cover them.
This isn't a typical DIY article, since you don't actually build any of the pieces. But,
the DIY is because you are assembling the system from parts, and by getting the parts
individually, and assembling them, you can save a lot of money over the cost of complete
systems sold for aquarium use.
This CO2 system can be assembled for under $150.00, but you need to do some
shopping around to get the various bits and pieces. You pay extra to get all
the parts in one stop.
First, a diagram of the complete system:
This shows a completed CO2 system, using my DIY CO2 reactor. Details about the
reactor can be found HERE.
Lets look at the various pieces:
The tank:
CO2 is stored at high pressure in the steel or aluminum tank. A typical tank is referred
to as a "5 pound" cylinder. It will be about the same size as a large fire extinguisher. It
has a valve on the top, and a pipe where the regulator will screw on. The gas in the tank is
stored at about 600-1000 PSI. The CO2 in the tank is a liquid. For this reason, it's
important to keep the tank standing up correctly.
The Regulator:
The CO2 regulator takes the 600-800 PSI coming from the tank, and regulates it, providing
a controlled output, typically in the range of 1-30 PSI. The regulator will have two
gauges, one showing the tank pressure, and one showing the output pressure. The output pressure
is adjusted by means of a knob or screw in the center of the regulator.
The Needle-valve:
Next is the needle-valve. This valve takes the CO2 down from the low pressure output
of the reactor, and allows you to adjust it down to just a few bubbles per second. Some
needle-valves will screw right onto the regulator, others have a tube fitting, where to
connect a piece of tubing from the regulator, to the needle-valve. The output of the
needle-valve is usually a tube fitting. That's where you would connect the output CO2
tubing. The needle-valve requires a low input pressure, usually not more than 10 PSI
or so. You set that 10 PSI on the regulator that feeds into the needle-valve.
The Reactor:
The reactor's job is to take the CO2 bubbles, and dissolve them into the water. Just
sending the bubbles thru an airstone doesn't work, as the CO2 bubbles will just float
to the surface and be lost. There are a variety of different reactors, which can be
purchased, or built.
Possibly the simplest reactor would be to feed the CO2 bubbles
into the intake of a power filter or canister filter or powerhead. This will help more of
the CO2 get dissolved into the water.
A more efficient CO2 reactor can be built or purchased. I've got a page showing my DIY
reactor HERE. Similar designed reactors can be purchased
from many aquarium retailers. Prices vary widely.
Parts cost and sources:
Now that you hopefully understand the parts, and how they work together, you can
start getting the pieces and building your own CO2 system.
- The Tank
A CO2 tank can often be purchased at a local welding supplier or industrial gas
supplier. In my local yellow-pages, I find them under "Gas-Industrial Medical Etc-Cylinder & Bulk",
or under "Welding Equiment & Supplies".
A typical 5LB CO2 tank should cost around $50.00, already filled with gas. Larger tanks are
also available for slightly more money. My 10LB tank was about $80. But be sure you've got
room for the larger tanks. While they are also available on-line and mail-order, the cost of
shipping a heavy steel tank normally eliminates any savings you might get by buying on-line. I
strongly recommend buying the tank locally.
The tanks sold by most welding and gas suppliers will be used. That is not a problem,
since most of the time, when you need a refill, you just trade your tank in for one that
is already filled. If you do purchase a brand new shiny tank, when you want to get it
refilled, you will need to search for a place that does the filling on-site. Most places
do not.
On the subject of refilling your tank, a refill of a 5LB tank will be right around $10.00,
and maybe a buck or two more for a 10LB tank. How long the CO2 lasts varies based on the
tank size, and how fast you are injecting the CO2 into the tank. In my case, with a high
bubble rate on my 75g tank, a 5LB tank lasts for 6 months. If your tank isn't lasting
very long, it's likely that you have a leak somewhere.
- The regulator
CO2 regulators can be purchased on-line (mail order), or at many welding and industrial
gas suppliers. Here is a picture of a typical CO2 regulator:
A regulator like this should cost somewhere around $30-50. Get one that has two gauges,
you won't save anything buying a single-gauge regulator, and the additional gauge (the
high-pressure one) will let you know BEFORE you run out of CO2 in the tank.
In addition to buying a regulator at a local welding supply or gas supplier, you can
also purchase them at a local home-brewing store. And there are many places
that sell them on-line. Here are a couple. I've not ordered from any of these
places, so I can't say anything specific about their service or products:
http://www.welding-direct.com/sinstagflowg.html
http://www.morebeer.com/
http://www.homebrew.com/
http://www.e-brew.com/keg-part.htm
http://www.kegworks.com/pages/draft/regulator.html
These are just a few I found. I'm sure there are others. I personally get mine from my
local gas supplier. They mainly sell them to home-brewers, and the cost is $40.00 (it was
only $30.00 when I first bought mine, but they figured out they could sell them for more!)
- Needle-Valve
The CO2 needle-valve can be a little harder to locate from non-aquarium suppliers. Some of
the larger/better welding/gas suppliers will carry needle-valves. Some super-high
quality valves allow you to adjust down to incredible levels (1 bubble per minute, etc), but
that kind of precision isn't needed. Valves that can control to that precision are expensive
(over $50.00). Typical bubbles rates that we use will probably start around 20-30
bubbles per minute, typically up to 2-3 bubbles per second. A needle-valve to do that
should be available for about $20.00. If you purchase your valve somewhere locally,
you should bring your regulator, so they can help you get any needed fittings / adapters to
connect the needle-valve to your regulator.
I purchased my needle-valve from www.marine-monsters.com. They sell it as a
"precision needle valve", and the cost is $19.00. If you purchase this valve,
you will probably need to find some fitting/adapters. Again, try your local welding
supply or gas supply place. I did this, and got the needed fitting for $5.00. I see
that on their web page, marine-monsters now sells the precision needle-valve with
airline fittings on both input and output. This will make life easy, as most CO2
regulators come with a hose-barb fitting already attached.
You can check them out at:
http://www.marine-monsters.com/front/products/fp-co2accessories.html
Note: Their site seems to crash netscape, so I'd suggest using Internet Explorer for that
visit, or call them at 617.494.8396 or email them at marinemonsters@hotmail.com
- CO2 Tubing
To connect the output of your needle-valve to your CO2 reactor, there are several acceptable types of
tubing. Regular airline tubing should not be used, since CO2 will be able to diffuse thru the
tubing, and the tubing can become brittle due to the CO2. Silicone tubing is one acceptable
choice, but it will still loose some CO2. Marine-Monsters sells a "co2 resistant" tubing. It's not
too expensive, and if you are already ordering parts from Marine-Monsters, you might want to get some
of their tubing at the same time.
Article Survey
Your feedback on this article would be greatly appreciated. All feedback is
anonymous, so please, be honest. Your input can help me create better content.
If you have any questions about this article, or if you feel that something is
incorrect or missing, please let me know via email at cgadd@cfxc.com
|
