Quote Originally Posted by chem geek View Post
Though lame, this link uses the term "sparkle" in reference to Borax four times. I don't know the mechanism, but clearly there is something about the way that boric acid reacts with (i.e. reflects) light.

Richard
Could it act as some sort of either flocculating or chelating agent to get very, very tiny particles to either precipitate out or dissolve in, allowing the water to reflect better? That is, to reduce opacity?

EIther that, or, as Richard implies, changes the index of refraction of the water (which, I suspect, any and all dissolved agents do).