I have MS and the only thing different that I found to be helpful is to have the water higher in the tub and the hotter the water the better the result.

I usually have the water covering my ankles and through seeing traditional Chinese Medicine Practitioners I learned about the hot water and the covering the ankles. It has proven to be much more effective with the pain in the legs and lower back, also eliminating the tingles in my legs.(25 years worth) I also see my Neurologist   to monitor the progress, we just did MRI and MRA of my brain and arteries. My doctor said that the foot baths have removed most of the blockages in my arteries and I now have great blood flow going to the brain. The more blood flow, the more Oxygen, the more healing, also at a molecular level the greenish color could be a number of possibilities, just know that what ever it is, it is a free radical that was pulled out through the electrodialysis. I would leave diagnostics up to the professionals, you may place yourself at risk if you think you can make a determination based soley on the color of the water, remember that water mineral and chemical levels will have a great effect on the color of the water, also remember that the foot bath is really clearing the limphatic (water)channels that process the elimination of toxins and foreign particles that the body can't immediatley process, so it really depends on what has been going on with your body or how long the toxins have been stored. Remember that your body is your best friend and works for you every moment of the day, but if it can't rid your body of the toxin or foreign matter it will most likely store it in fat cells until it finds a way to dispose of it, so you may be seeing signs of stored matter. Anyway, the foot baths are just a catalyst for your body to start naturally detoxifying through it's natural process of elimination, it can take away the barriers so your own system then can take back over. Leave diagnostics to the professionals, provide service and support for a process that can help get their bodies working properly by opening up and cleansing the lymphatic channels and assist removing heavy debris that your body may not be able to naturally eliminate.