The invention relates to a easily adaptable or DIY installation water cleaning device on any existing spa or pool, said cleaning device including an electrolysis module equipped with a particular boron-doped diamond electrode on silicum substrate. The inventions also relates to a method to clean water on spa or pools using a water cleaning device comprising said particular boron-doped diamond electrode present on the elecrolysis module. The invention also relates to electrolyzed bathing water for use in the treatment of inflammatory diseases of the skin and for use for use in the treatment of wound healing of the skin.