After effects of Sylk - low PH 17 hours later

So after using Sylk last night, my ph today is at 4.4. This is the lowest it's been (it's normally around 5 - 5.5).

Could it still be that using Sylk last night is keeping it low?
Is it the copious amounts of caffeine free diet coke I've been drinking?
Is it because I'm a week or two away from ovulating still (and it will rise in the next few days)?

I wish I knew the answer! I just wondered if others had found Sylk has a long lasting ph effect?
Thanks

Yes, it can absolutely be the Sylk, but of course your pH will def. be low a week before ovulation!! It WILL go up, mark my words! ;)