AlabamaJack said:she probably will want me to wait until I use the liquid up...
These things are known for accidently dropping though.
Seriously, I've had a koi pond for 9 years, and those "colour" tests are often completely unreliable (and make people take the wrong kind of measures).
The tester Pepperfreak linked to is a good investment if you worry about pH. It comes with a tester fluid of 7.0 so you can calibrate the device.
Another way is to send a sample of your tap water to a lab for a thourough analysis (which would cost less and gives you a complete overview of all trace elements etc.)
If pH is too high, you can always collect rain water - which will be more acidic - and mix it with the tap water. (I understand peppers prefer slightly acidic conditions - 6.5?).