Hi. I actually bought a ion foot bath, after going for five treatments. Mine was not black but was always orange which indicated a had joint problems. I did feel tired afterwards, but had great sleep. Lost about 6 pounds after the five treatments and I don't feel hungry. They say for the fist time you should have five treatments and have them every other day so that your cells and re-coperate. Then wait a week and do another five. After that you only need to do once to three times per month.