pH questions

["Francis Brian O'Carroll"]

> From: "Ed Pon" <edpon@hotmail.com>

> If you don't have a lot of buffering, the anaerobic bacteria that breaks 
> down waste products will use oxygen, emit CO2, and I've been told, 
> acidify the water.

What about other products such as nitrates and nitrites? Can they acidify?
As I remember, ammonia (another fish waste product) dissolves in water
to be an alkaline solution.
Howabout products from leaching or decay of driftwood?

> A friend of mine who lived in San Francisco where 
> the water is extremely soft, couldn't change his water fast enough in 
> his 55 gallon fish tank to keep the PH above 6.

I have the same problem in Tokyo. Lowest reading recorded was 3.5.
And when I added a small amount of ph up salts (according to the pack,
enough to raise the ph by 0.2 points, it shot up above pH 8. Tap water
is pH 7.2