"Iain Miller" wrote in message
...


Increasing the Kh will not increase your CO2 level....only adding CO2 does
that (!)
I have read that water with a high KH holds CO2 better than low KH, so
that's why I'm attempting this.

Increasing KH without altering CO2 will increase your Ph so I'm not quite
sure how you managed to add Baking soda & not affect Ph....it doesn't
compute - suggest you test it again.

I've read that the pH will rise, but not necessarily in direct proportion.
My understanding (such as it is) was that I would be able to raise the KH
somewhat, without an immediate, correlative effect on pH. So I figured I am
OK so far. But will check it again tomorrow.

Quite often you will see tap water
having a lower than expected Ph level - this is because it sometimes
(usually) contains artificially high levels of CO2 when it comes out the
tap. Water that has just been filtered through peat does the same thing
(only to a much greater extent). In both cases the excess CO2 will escape
over a matter of hours & the thing will settle back to the standard
2-3ppm.

You seem to have understood that there is a relationship between KH, Ph &
CO2 but just perhaps not how it works.

Yes, that's often my problem

The two variables are Kh & CO2. The
Ph is the product. Altering one of the variables (CO2 or Kh) will alter
the
product (Ph) but it won't affect the other variable. So adding Kh won't
change your CO2 level & playing with CO2 levels won't affect your - Kh but
altering either one will affect the Ph.

Short answer, in order to increase CO2 you need to add it one way or
another.

I'm hoping that the considerable expense of dosing Excel regularly at fairly
high rates will help with the CO2 level, and that increasing the KH will
make the CO2 more available to the plants. I'm not looking for spectacular
plant growth, just a decent looking display that will enhance the tank and
make life more enjoyable for the fish. Thanks for your contribution to my
education.