From everything I've read on the subject over the past 2-3 years, the pH of properly made, cured, CP soap will always fall around 10 to 10.5. This is based on the info I've gleaned from another forum I belong to we have a chemist on board. She's tested many CP soaps in the lab and she's never seen a properly made, cured, CP soap fall below 10. She uses a pH meter which is much more accurate than the pH strips which she says are notoriously off quite often by 2 or three points where soaps are concerned. Other soapers with pH meters have confirmed her findings. Their combined conclusion is that is quite a moot point to test the pH seeing as how it consistently comes to rest between 10 and 10.5 when the soaps are fully cured, no matter what you do to try to make it lower.
They say that a better test in order to make sure your soap is good to go is to just check for 'zap' or lye heaviness with the tongue test. Wait a few days after cutting your soap before doing it though, as the soap is still going through some chemical changes for those first few days and can still zap that early on, even though your batch is not lye heavy. I like to wait 2 weeks before tongue testing my soaps in oder to give the soap enough time and then some to go through its major paces. HTH!
IrishLass
