ᐅ Black grout is sometimes turning white

Created on: 7 Jul 2020 20:21
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Golfi90
Hello everyone!

To match our rather dark 60x60cm (24x24 inches) tiles, we had our bathroom grouted in black.

At first, all the grout lines were nicely black.
However, after some time, some of the grout lines have started turning white.
For example, when they get wet in the shower, the grout turns black again.
When they dry out, they turn white once more.

This effect is consistently reproducible.
What can we do to fix this?

As far as I remember, pre-mixed grout from a bag was used for grouting.
Golfi908 Jul 2020 07:33
We do not use aggressive cleaners since these are porcelain stoneware tiles.
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guckuck2
8 Jul 2020 07:36
Colored grout never stays like new. When cleaning, dirt from the tiles gets rubbed into it.
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Lumpi_LE
8 Jul 2020 09:25
It’s like this in some places for us as well; it must be lime, and we basically have no lime in our water.
Tolentino8 Jul 2020 09:42
In hindsight, I also thought that choosing all those stylish dark floor tiles wasn’t the smartest idea, but you always know better after the fact.