Keeping a steady pH

This is an e-mail which I receive from a discus mailing list that I thought would be helpful. I worked for me.

"Dear Discuslovers,

>My advice would be to age your water for a couple
>of days in a clean, open plastic (not glass!) container
>in the same room as your aquarium and then measure
>the pH.

>My question: Why not Glass ?

Greetings,

Good Question. Ordinary glass, also called soda glass, has a lot of
sodium oxide in it (aaded as sodium carbonate in the raw mixture).
This is done to lower the melting point of the glass with a couple of
hundred degrees with considerable savings in energy.  Soda glass is
used for making bottles and window panes.

Soda glass slowly dissolves in water. It depends on the sodium
carbonate in the mixture which can vary between manufacturers. I have
made meausurements, using degassed and deionized water, and found
chanes from 7.0 up to 8.2. One would not want to add this kind of change
to the change of the water which one is actually interested in.

Boro silicate glass (like the Pyrex brand) is something different. It
dissolves far less. But it requires a much higher temperature to become
molten. That is why it is also far more expensive. You may use it freely,
like most plastic containers.

Keep the container with source water also open. There may be some
gases (of which you are not aware) which will disssolve in the water
and may change its pH. There may even be substances already
dissolved in the source water which may become oxidised by oxygen
in the air.

Please, do not think that the use of soda glass for the panels of
an aquarium is dangerous. Initially some of the sodium oxide will
"leak out" in into the water and even then not in dangerous amounts.
But after a couple of months even that will become much less.

The main point is to find out what becomes of the pH of the source
water after a couple of days without the plants, fish, rock, gravel and
wood in the aquarium adding additional changes to this change.
Should the pH in the aquarium itself then become lower or higher
than this reference value. then one can seek for the source of this
change. For example, if the increase is higher, it will most probably
from a rock or a component of the gravel."



My tap water in 7.0 but after a couple of days, it rises to 7.6+. It really sucks. Im now trying C02 injection. I hope it works.