the farther away from the time you take the Miracle-Mineral-Supplement to the Vit C the better, if you are taking it every 12 hours , I would try and wait at least 6 hours.
If you have not had any big purging, try taking it with just distilled water and no juice after activation. Even thought Jim Humble says "NO ADDED Vit C", Vit C is Vit C if it is natural or not. I noticed that I could get up to 16 drops with grape juice, but not with Distilled water.
Toward the end of the second book, he says NOT to store it in a Frig. as just the light going on and off is bad for it. Just in a cool DARK place.