ph meter question

I bought the Apera ph meter. I calibrated it. It reads the 7.0 water solution but when I put it in a thicker serum it doesn't just stay on one number it fluctuates a lot. thoughts?


  • PerryPerry Administrator, Professional Chemist
    Is it an emulsion or water based formula?
  • good question. it has water in it but then humectants like pca and glycerin 

    I don't know exact measurements because I didn't make it.
  • PerryPerry Administrator, Professional Chemist
    Does it have oil in it and any emulsifiers?  maybe you could list the ingredient list.

    But in general, the pH meter may fluctuate a little in the beginning, but it should come to equilibrium and stop moving. If it is an emulsion, then it might not get completely steady.
  • water
    Sodium Hyaluronate
    sodium pca
    soidum lactate
    witch hazel extract
    licorice extract
    Xanthan Gum 


  • PerryPerry Administrator, Professional Chemist
    With that list, it shouldn't jump around.
  • edited May 21
    what ph meter do you recommend then because this one still reads the calibrating solutions correctly but is jumping all around my acid serums. :(
  • ozgirlozgirl Member, PCF student
    How much does it fluctuate? Is it just the decimal place jumping back and forth between two numbers (eg. 4.1 to 4.2)  or does it just take a long time to reach a reading.

    We have found that some some of our products with low levels of ethanol take a while to reach a stable pH reading. Does your witch hazel have any ethanol?
  • @ozgirl
    it'll run up and down from 0-9 it doesn't stay on or @ a number. I don't know if the witch hazel has ethanol, I didn't make this one. If I place it in a toner it sets on a number or even a very runny cleanser but for some reason when I put it in an acid serum it goes crazy.
  • ozgirlozgirl Member, PCF student
    That is very strange. Sorry I don't have any other suggestions. Maybe try contacting the manufacturer.
  • @ozgirl
    thanks for your help! :)
  • I bought this one:

    After reading some of the comments on this site...and have been happy with it.  There is also a cheaper $29 version of it....on the same site.
  • @Graillotion
    awesome! I was totally looking at that one. Thank you.
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