Another thought:

It seems that one can achieve a maximum CO2-water diffusion *rate* with a
powerhead/filter intake + bubble system, but retention of the CO2 will be
based on the water chemistry (pH, kH, not clear on this, but indeed it
seems chemically related).

The new "3-d" NutraFin/Hagen Diffuser seems to be a new spin on the
inverted bell system, by forcing the CO2 to move throughout the water ,
but without any outside assistance (like the powerhead/filter intake
method), while retaining the simplicity of a bell style system (the ramps
are inverted upside down), but still seems to belong primarily within the
inverted bell family of reactors.

It seems that inverted bell systems are better suited under conditions in
which the water chemistry (that is naturally or unnaturally (chemically
assisted)) is better able to retain CO2 since there is no mechanical aid
to increase the CO2-Water diffusion *rate*.

Likewise, Powerhead/Filter + bubble systems can be used under conditions
when you have water chemistry that is naturally less inclined to retain
CO2 but have a generator that can output alot of CO2 (the 5lb/10lb CO2
pressurized canister method) whereas inverted bell systems have the
restriction of being in water that retains/absorbs CO2 well.

In short, I think people (including myself) who have an inverted bell
type reactor should think twice about the efficiency of the reaction
method, and that reactors that don't "overflow" (big gulp of CO2 bubbling
to the top) don't necessarily mean that CO2-Water diffusion is operating
at maximum capacity.



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