At what point does a line of red appear in the solution itself? Do not understand. Please clarfy "A light meter would be handy if available. No light meter available"
A TDS meter only measures ions, not particles. The beam from a red laser pointer will be scattered by particles, even the smallest of these. The beam will vary in intensity in direct relation with the amount of particles. You will first see the beam in a pitch dark room and as the number of particles increase it will also be seen in normal ambient light.
