Thanks my fault - it should be 48ppm instead 1000ppm
I will try to heat it and add maltodextrin if it does change the color even more...
I have tried 2 batches
1. 0,6mA - around 4,7-5,5V
2. 1,64mA - around 12 - 13V
Electrode distance 21cm
Both with identical results - clarity/final PPM/colour after reduction. I dont think there is any issue with such low voltage.
Bright color does not mean always lower concentration. It could be due smaller particle size at the same ppm.