Okay, here are the photos, you can easily see the rusty spots and purple hue on my plants. I watered them with clean water for three days, and today I measured the leaving water and it was 820 ppm. That is why I watered the plants with the new mix 1/0,5/3/0,7 in the evening. The leaving water was 1200 ppm.
I watered Big Bang with clean water as well and cut off some big leaves. I decided to pinch off the tiny colas on the lower branches, dried them and smoked some other raw buds. Well, it was a quite nice joint, but of course not perfect, it is just too green for that. And the taste was a bit chemical.