Re: Using Bubbles to measure CO2 levels

["S. Hieber" <shieber at yahoo_com>]

> I frequently see people on the newsgroups asking "how many bubbles
> per second do I need for 15ppm CO2?"  but it's impossible to
> give an answer.   Bubbles are not a valid measure of CO2 levels.


Well yes -- but then again no.  Lot's of things affect how many bubbles
from your particular CO2 setup should go into your particular tank per
hour to yield a specific CO2 level.  So, no, you can't say, a priori,
what will be the right rate for your situation.  But, once you have
things stabilized, you can count the bubbles.  Then yes, so long as
they don't very much from that rate, you can be pretty sure that the
CO2 levels are remaining about the same.  You can check from time to
time with pH/KH measurements and the the pH/KH/CO2 table; but if you do
you will find that stable bubble rate means a stable injection rate of
CO2.  In fact a quick glance at the bubble rate can indicate when your
CO2 tank is getting low -- the pressure on the "Low" (output) side of
single stage regulators rises as the pressure on the "High" (input)
side.

Being an ersatz measurement isn't quite the same as being an invalid
measurement.  ;-)

As for people asking for the "correct" rate to use:  A person's gotta
start somewhere.  I think it's reasonable to suggest a target rate to
start with, and how to proceed from there.

Scott H.

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