Don't. The chemicals used to lower pH destroy the alkalinity or KH. The KH
is a buffer that helps stabilize the pH. If the KH is lost, then you are
more likely to have a pH crash at worst or very unstable pH at best.
Neither is good for fish. The fish will do fine in almost any stable pH
from about 6.5 to 9.0. Some plants utilize nutrients better in lower pH
ranges, but if the pH is jumping from 6.5 in the morning to 9.5 in the
afternoon, then I don't think the plants will like it either.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"KRF" wrote in message
...

Just set my pond up Wednesday. Tested my Ph yesterday, and it 7.5.
How do I lower it to 7 or below. The book I have from the Library, say
a little under 7 is ideal for plants and fish, is this true? Thanks