We use chromatic alginate in our peds room because the purple-to-pink shift calms anxious kiddos, but what’s the original trick behind it — temperature-sensitive dye or a pH indicator? I remember mixing it at 23°C in school and being told the color was our “kid-friendly timer,” but I never learned the real chemistry.
It’s mainly a pH indicator riding the trisodium phosphate → calcium alginate reaction; temperature just speeds or slows the same purple→pink “kid-friendly timer” (not a mood ring). If your water’s acidic or too warm, the cues can drift — try 23°C distilled water and the IFU times; a few brands do add thermochromic pigment, so which one are you using?
Think of it as a staged color system: the phosphate buffer drops during set and flips a dye, and some peds mixes even stack a second indicator to make the purple→pink pop. At the 23°C you mentioned the timing is calibrated, but hard water, old tubs, or warm hands can nudge it — try distilled water and a fresh jar and the “kid-friendly timer” lines up again. Quick read: Cavex ColorChange: een intelligent alginaat.