hi francine-
from my limited exposure as an architect to these kinds of things, it's my understanding that water tables (the underground level of water that, among other things, supplies wells) can rise and fall according to rainfall, drainage conditions, snow melting from nearby mountains, etc. the ground generally acts as a filter, imparting varying degrees of mineral content to the water depending where you are in the country and how deep your well is. it's reasonable to assume that a (large enough) change in water level affects the composition of the well water, especially its hardness (which in turn might affect the pH due to buffering).
say for example the groundwater is naturally a little more acidic than rainwater (due maybe to organic material, chemicals, etc.). normal rainfall 'dilutes' the acidic water and leaches more of the mineral content from upper levels of the ground. maybe the lower level of your well is surrounded by rock like quartz/granite, and the upper levels have more limestone...so in that case you'd get a higher pH and higher hardness during normal rainfall conditions.
but then again i may be totally wrong; i'm not a geologist. it's only a somewhat educated speculation on my part.
hope that helps, anyway.
-andrew in SF, but born in MD (Hagerstown)
-----Original Message-----
From: Uneekwa [mailto:francinebethea@excite.com]
Sent: Monday, July 26, 1999 10:06 AM
To: apisto@listbox.com
Subject: ph magic
Would someone know why the ph values of water would change in 24 hours?
My water is off a well. When I first started this hobby in Sept. of 98 the
water tested 7.6 and very hard. Last night I tested the water and the ph
was 6.5 and it tested very soft; same water source. I accidentally left the
tube on the stand and this morning the water in the vail was extremely blue.
Why would this happen? Could the drought affect the water parameters?
Francine in MD