Something to note for all pH meters is the age of the meter; the gel seal inside the meter is only usually guaranteed to keep its seal for 2 years after being manufactured, although the gel seal may last much longer this.
Digital meters such as the pHscan 1 have the month and year of manufacture on the inside of the battery lid. I suggest checking it when purchasing as some hydro stores may have slow stock turnover.
Editors Note: The PH Scan 1 and 2 can have the glob and wick within the tip replaced (I get mine changed at my local hydro shop for $10 AU)
These Documents contain information gathered from many Online Communities and all possible references have been given to the authors of each individual article. For any discrepancies in this please contact "overgrow2@gmail.com" ....ps enjoy