Viakal stained bathroom tile grouting blue. How do I get rid of the blue?

[Pippagled]

As the title suggests, using Viakal to clean my bathroom has turned the grouting between my bathroom tiles blue. What can I do to remove the blue? Any recommended products or formulas?

Sodium PERCARBONATE (not bicarbonate) is the magic ingredient for most stains. not sure in this particular situation but it is where I would start.