I use good ol' pH paper.
http://www.neighborhoodlink.com/org/...515131447.html
pHydrion is a reliable brand, and should run about $6-10 for a 15 ft
roll, which is good for a couple hundred tests.
Nasco is (ime) a reliable source for this sort of thing:
http://www.enasco.com/Buscar.do?q=pHydrion&x=0&y=0

You can also use the pH indicator on a swimming pool test strip.

Kay