Hi ya
I have put a post elsewhere on HP about Aqua Detox. I had one once and it was tingley and pleasant (the treatment was offered free). But if I was going to pay the typical £30 for a 30 minute session, I would have a proper Reflexology treatment, at a similar price at 60 minutes per session.
When I saw the discolouration of the water and smelt it, it smelt like an oxidisation, i.e. rust.
Any stimulation of the feet will make you feel good. My issue with Aqua Detox is that it is expensive for what it is, a plastic footbath, electrode and a digital regulator/timing circuit*, and some of the therapeutic claims are quite frankly mumbo jumbo (but you could say that about Reiki).
Cheers
Reiki Pixie being cheeky again (but means it)
* Personal opinion based on my previous career as a radio & electronics technician involved in the maintainance and repair of communications equipment.