I have calibrated two cheap ph meters using calibration solutions mixed with distilled (and ozonated) water.
I also have a book of universal indicator ph strips.
When I measure a fertilizer solution with the paper it indicates a ph of 7 . When I use the two calibrated meters I get a ph of 5.3.
The fertilizer solution does have some color but I do not feel as though it is obscuring the ph papers reaction.
I am not sure why this is and hope someone here might be able to help explain this .
Sorry if this is spoon feeding . Thanks. |