Can anyone recommend a pH tester? Preferably inexpensive (but not the kind of inexpensive means its a piece of shit). I was thinking about getting http://www.amazon.com/Luster-Leaf-1601-Rapitest-Soil/dp/B0000DI845/ref=sr_1_10?ie=UTF8&qid=1338156349&sr=8-10 even though its not electronic.