Grey grout turns white

[Walt]

Cleaned some slate today. It wasn't very dirty so I just used a cleaner from coastwide labs. Mopped on scrubbed by hand. Rinsed with wand. It was to uneven for rotary.

As it dried, all the grout turned a much lighter color of grey. Except the bath room, which has same tile and grout.

What gives? How do I fix?

 

[danbrown]

It was too uneven for a rotary (im assuming you mean a turbo or the like), yet even enough for a wand? Now that doesn't make any sense at all...

Was this coastwide labs cleaner a degreaser or what? What was your dilution rate?

Perhaps the bathroom grout is still dirty.

Moar pics....

 

[boazcan]

Post some pics Walt.

Might have been a different shade in the bath, maybe added later to match the dirty grout color.

 

[alazo1]

Efflorecense?. Hit a line of grout with acid to see how it reacts, bring a small wire brush. You didn't seal it right?.

 

[richard]

Efflorecense?. Hit a line of grout with acid to see how it reacts, bring a small wire brush. You didn't seal it right?.

efflorecense probably. sometimes a wire or stiff brush alone takes care of it.

 

[getdusty]

Is there a coating on the grout? Slate is often sealed with a topical sealer, or wax even. It coats the stone and the grout.