Why does the waste in the middle of the floor go black?

Many of the cleaning products used in bathrooms are unsuitable for prolonged contact with electroplated finishes such as Chrome Plating. It is common that these products are used when moping floors. In the shower, the residue left from these products is washed away through the regular use of this facility. However, in the case of the Floor Waste in the middle of the bathroom, the residue of these cleaning chemicals is not washed away, and therefore starts to damage the finish.
Please see Care Instructions to see more details around appropriate cleaning and care practices.