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Re: DIY CO2 diffuser

On Wed, 26 May 1999, Joe Anderson wrote:


> but my pH has remained constant at 7.6-7.8 with a Kh of 11-12*.  Looking at
> the chart this means I am getting no more CO2 than what is provided by the
> atmosphere above my tank (is this correct)??
> Joe Anderson


The charts I saw don't go as high as 11-12 KH.  Using a formula, I figure
the CO2 content at 6 to a little over 10 ppm.  This is 10 or 20 times
what you have in plain water contacting air and around twice what you
would probably have in a normal, unplanted aquarium without plants.  6 to
10 ppm should be fine for most tanks.

If your pH is 7.6-7.8 hours after the lights come on, then you probably
don't need to worry much about the CO2 content.  If the pH is 7.6-7.8 in
the morning before the lights go on and climbs to 8+ after the lights are
on then you probably want to add more.  If your pH doesn't change much
from night to day, then photosynthesis in your tank is probably controlled
by some factor other than CO2.

You can do what you want with the diffuser but it won't do your plants any
good unless the plants are now using most of the CO2 you're providing.
they are using up their current supply then you should be able to measure
night-to-day changes in the pH.  If the pH isn't changing and growth is
slower than you want then maybe you should look to other causes.

Roger Miller

In Albuquerque, where the heater runs in the morning and the air
conditioner runs in the afternoon.