It is not clear what kind of "foot bath" you took. If it was simply soaking you feet in filtered water, great. You must have had some dirt on your feet. I suspect, however, that you may have been using one of those electric devices on the market now that allegedly takes toxins out of your body through your feet when you fill the devices basin with water, turn the device on, and soak your feet in the basin. So sorry to be the bearer of sad tidings, but all such devices are scams. There is no way that toxins in your body can be pulled out of your feet by soaking the feet using such a device. The "dirt" or "toxins" that you see discoloring the water as you soak do not come out of your body. They come from the machine's electrodes which are decomposing in the water much as the electrodes of vaporizers flake off in the water in the vaporizer well. If you doubt this [which I can understand] just test it by running the foot bath device sometime without putting your feet in. The water will get just was discolored without your feet soaking in there. Fraud in advertising is very upsetting. Any additives that come with the device to help you "detox" may actually be making the electrode deteriorate faster.