CO2 reactor

Here's my (cheap) CO2 reactor:
A powerhead pushes water from a corner overflow via a 3/4" PVC pipe to a 
spraybar (submersed) at the other side of the tank. The PVC runs along the
outside back of the tank.
Along the way, there is a 90 degree down elbow that leads into        
a 8" long black ABS pipe. Out of the ABS, the flow is once again into  the 3/4"
PVC, up into the tank (see drawing). The ABS is filled with 6 or 7 bioballs.
CO2 is injected into the powerhead intake (actually a quick-filter sleeve),
chopped up by the impeller, and flows into the ABS pipe. There, any undissolved
gas gets trapped at the top. Efficiency is 100%.

 |---|===========+              +===========> to spraybar
 |P.H|         | X |           ||
 -||--         | X | ABS       ||
  ||           | X |           ||
 quick         |~X~|           ||
filter         | X |           ||
sleeve         | X |           ||
 CO2 in        - ||-           ||
                      3/4" PVC
Note: The top of the ABS has a screw top, to clean out anything that gets past
the filter sleeve (once every 6 months).
Flow rate is fairly low. I will replace the powerhead either with a stronger
one or a submersible pump.
This design is not forgiving to CO2 dosing errors! Due to its high efficiency,
incorrect (i.e. too much) dosing will result in a quick pH drop.

I hope someone can use it.

in the Canadian Winter Wonderland - every winter I wonder what I'm doing here