"kush" wrote in message ...
I recently experienced a near *implosion* when I hooked my plastic soda
bottle up to the venturi on my powerhead for the first time. There was just
enough suction produced to partially collapse the flimsy plastic. Problem
was easily corrected by using a sturdier juice bottle. Other than that, no
problems of my own, or of others, that I know of in many years of using DIY
setups.

kush

Here's what i do.

From the co2 reactor i have a tube that goes into a "bell" which is
the bottom couple of inches from a cola bottle, upturned in my tank.
The tubing from the reactor enters through the center of this bell at
the top. This is the standard way of doing things i think. What i have
also done is put a tube in the side of the bell that goes to the
venturi on my internal power filter. This does 2 things

1. As the bell fills up with co2, it reaches the point where the hose
from the venturi is, and the venturi sucks the co2 out of the bell to
a level just below that of the pipe in the side. This blasts tiny co2
bubbles throughout the tank which get absorbed.

2. When not sucking co2, the venturi pulls the water below the level
of the co2 through the pipe, thus providing the required water
movement on the co2/water boundry in the bell

Cue bad ascii art.....

tubing from co2 reactor
||
|| @@
/----||-----\ //===================||####### co2 BLAST!!
/ Co2 || \ || pipe to venturi -----
/______||_______\ // | |
/ || ====/ power filter
/ o || H20 \
o
Tube lower than co2 level = bubble counter

It works very well indeed, i get really high co2 levels for a diy,
about 25ppm in a 40 gallon

Hope that helps.

Mark