PR> Litmus is quite accurate if it is carefully used and you have experience
 PR> knowing how to recognize the inflection point.  As are all the other pH
 PR> indicators, methylene blue, methyl red, etc.  But each has only one
 PR> particular pH point at which they change.  The inaccuracy I was speaking
An aquarium tester will cover a range from around 6.0 to 8.0 in PH, if not 
MORE. I just can't recall the precise numbers.
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