linda mar wrote:

Hi all,

I ended up with too many stem plants to plant in my aquarium (or at least
not until some of the ones planted in the aquarium doesn't survive the
transplant shock).

Since I didn't want to discard it (anacharis, milfoil, lysmachia) since
they're pretty on its own accord, I bought a very tall glass vase (~20in
high, 8in diameter. more like a cylinder than a vase), filled the bottom
with sand, and dumped the plants in there with a drop of Flourish.

In the tall thin container you describe, the plants will suck all the CO2 out of
the water, which will drive the pH up. Since the surface area and circulation
are so low, the water will remain low CO2, high pH.