test kit & C02

Hi Folks:
         Not being very good at chemistry-but certainly making an effort to
improve- I'm wondering if anyone can tell me if the Aquarium
Pharmaceuticals water hardness kit measures GH or KH. The regents are
labeled sodium hydroxide and calmagite solution.

Also, recently I put together a C02 injection system-luckily found a near
new used regulator and bottle for a very reasonable price-but now I'm faced
with a bit of a dilemma when doing water changes.

The PH of my tank has settled nicely down to 6.8-7.0 but the PH of the
water used in my weekly 25% water changes is up around 7.4.  I'm worried
that this might be too much of a shock on the system especially with some
of the more sensitive plants prone to metldowns such as crytocorynes.

How do other people on the list handle this situation?

many thanks for all the  wonderful information and inspiration!

John Cochran
Photography & Digital Imaging
British Columbia Flyfishing Resources
jcochran at pinc_com