RE: Olga's Ph flux due to CO2 injection

> [Olga wanted to increase the KH in her tanks]
> > Well, my reasoning was to prevent pH swings. If I test in the morning
> > the pH is about 6.5 - 6.6 when I test at night it's about 7. I assume
> > this is because the plants don't use the CO2 at night -- but hardening
> > up the water by adding more baking soda or some calcium carbonate
> > would hold it steadier -- no?

I've been lurking here for a while and the info provided has inspired 
me to convert a 55G to a plant tank. Thanks all!  

I may be way off base here but in theory this might work.  I have not 
tried it yet myself because I have not quite finished preparations for my 
conversion to a plant tank .  As I understand it adding air bubbles will 
dissipate the CO2 in water.  So why not set an air pump and bubble wand on 
a timer so it will run at night.  This will drive off the CO2 at night and 
prevent a CO2 buildup and the plant uptake of CO2 will do the same during 
the day.  Without the CO2 buildup your Ph wouln't decrease.  You could
experiment with an air valve to put in just enough bubbles to stablize 
your Ph day and night. 

Since I'm pretty new to plants I could be absolutely wrong but I am 
curious to see if anyone has tried somthing like this.