DIY CO2 Tips

[Chuck H <grendel at usit_net>]

Slow day at work today, so I just thought I'd pass along a couple of tips 
that will help minimize some of the potential risks associated with the 
typical DIY CO2 setup.


TIP #1:  FILTER & BUBBLE COUNTER

If you want to minimize the possibility of stuff making it from your DIY 
rig to the tank under normal conditions, here's an old method you can use 
to filter the gas.

You'll need:

     * 1 empty 20oz soda bottle w/ cap
     * 11" length of 3/16" OD rigid tubing
     * Epoxy glue
     * Knife
     Optional:
       Drill and bit


1. Cut the tubing into one 2" and one 9" piece. With the knife, score a 
line around the tube where you want to cut it and snap the tube in two.

2. With the tip of the knife or an electric drill, drill two small holes in 
the bottle cap.  Drill from the bottom side so you don't push the cap seal 
out.  The holes should be small enough such that the tubing fits 
tightly.  Be sure the holes are in from the edge of the cap enough that the 
area where bottle and seal meet is not compromised.  If you use an electric 
drill, place a block of scrap wood under the cap so you don't drill into 
your table or counter top.

3. Trim off any residual plastic from around the holes and scuff the top of 
the cap around the area of the holes with the knife edge or sandpaper (for 
better glue adherence later).

4. Push the tubing pieces, from the bottom (seal) side of the cap, through 
the holes.  About 1" or so of each piece of tubing should extend above the 
top of the cap.  I stagger the heights of the tubes about ~1/4" so 
attaching air hose to each tube is easier.

5. Epoxy the tubes in place.  This not only seals the area around the tubes 
but provides some structural support as well.  I use a toothpick to work 
the epoxy around and between the tubes.

6. Once the glue cures, you're ready to go.  Fill the bottle about a third 
to halfway full of water -- just be sure the end of the long tube is a good 
way under the water line inside the bottle.  Attach the air hose from the 
reactor to the long tube, and attach the air hose leading to the aquarium 
to the short one.

Now you've got an inexpensive filter/bubble counter that should last you a 
long time.  It also works great as a bubble counter for compressed gas or 
for filtering air from a bladder pump.


TIP #2:  TIP PROOFING 2 LITER SODA BOTTLES

Since soda bottles are designed with CO2 and pressure in mind, they seem a 
natural choice for DIY CO2 setups.  But they do have one drawback and that 
is that they lack a sturdy base and can tip rather easily, especially if 
they are overfilled.

One solution is to strap the bottle to the side of your stand.  This can 
easily be accomplished with duct tape, but a long, *releasable* zip tie 
attached to the wall of the stand will not only be more secure but also 
cleaner.  A heavy duty stapler is great for attaching the zip tie to the 
stand, but a large headed screw or two will also hold the tie in 
place.  For maximum stability, use two ties placing one high and one low on 
the bottle.

If attaching the bottle to the stand is not a possibility, simply glue the 
bottle to a flat base.  Any flat, rigid material about 1/8" or more thick 
should work well.  The base need not be overly large, a 6x6 inch area 
should do.  Be sure to center the bottle on the base as well as you can.
--
Chuck Huffine
Knoxville, Tennessee