pulchripes
- 54
- 18
Needing to calibrate my PH pen, I got some cheap packets of salty and sandy stuff off amazon, two dissolved but the 9 didn't, is the 9 important to calibrate if I'm only dealing with wanting ranges of 5 and 7 accurate? Pretty much everywhere I'm looking I just see 2 part test kits 4 and 7, the 9 seems uncommon. Also not sure of the accuracy of the solutions but they seemed not too bad apart from the 9 which stayed in like a sand state and read like 8 before calibration, now worried my pen is all out of whack, tested normal water and it read 6.5 where it would read 7.2 ish when the pen was new about a month ago. Some of the solutions are a ludicrous price for some reason, these have good reviews but will I also need the 9?
