adwa ph pen?

just got myself this pen and need to know if i really need to purchase ph10 buffer solution

purchased 4 and 7 2day r these pens 2point calabration or 3 point ive read most are 2 point ie 4-7 solution to calabrate

hope u understand what im getting at lol

thanks for replys

only ever used test kits so this is new to me

when i bought my ph tester it was already good to go.

but i bought the ph 7 and calibrate it to and followed the instructions.

just follow your instructions .