How to get white of Indian slate tiles.

[Gonzo61]

Hi,
We washed our Indian slate floor with stone floor cleaner and whilst it has cleaned them well, they have dried dull and with a white haze on them.
From looking at pictures I don’t think it’s efflorescence.
Does anyone have any suggestions what this could be or how to correct it?
Thanks

 

[Jedstiles]

What colour grout is it white or silver grey. Not that it really matters, to me it looks like it could be grout or tile adhesive residue that was never cleaned off properly, if it is get some grout cleaner from Topps others are available. Wire scouring pad and elbow grease. It may also mean your slates are porush and taken some colour from whatever cleaner you used, have they ever bean sealed. You could try colour enhancing sealer which should bring out the darker colours, if this is going to work you will be able to make the stain disappear just by putting water or damp cloth over it, lots of slate is actually ugly, when dry and not sealed . Last resort get either bag of darkish grout or brick die and apply a wash to stain it darker.
Probably you have washed the old sealer off and you are seeing it's natural colour for the first time in that case just reseal.