Off White shower grout with black spots !

[ED007]

Hello, any ideas what maybe causing this stains in a shower grout and how to get rid of them. The grout was Sealed about 3years ago.

Thanks.

 

[Dumbo]

Black generally indicates mildew . The tiles don't look like stone so I would say bleach or grout cleaner .

 

[ED007]

Thank you ! Any preference on grout cleaners for mildew stains then ?

 

[Dumbo]

Thank you ! Any preference on grout cleaners for mildew stains then ?

I would use lithofin grout cleaner , but I do not know if this is available in Canada.

 

[Time's Ran Out]

Scratch at 1 to see how deep it is.
My initial thought was adhesive in the joint which has gradually discoloured.
Wall or floor of shower - still done well for 3 years+.

 

[Glynn]

Does the staining not look too rectangular/square for bacteria? The staining is only on the corners. Could the spacers still be in there and something is causing the reaction.

 

[widler]

Im with glynn, looks like the spaces ?

 

[ED007]

Thank you all for your replies and suggestions !! It ended being « Mold » as a little Bleach and some elbow took it out. Now, the next question .. what’s the best sealer for this type of use case ??

Thanks and enjoy your 4th of July !!

 

[Dumbo]

Its more about ventilation and warmth . If you have a shower cubicle leave the door open so air can circulate in there so it dries properly . Use an extractor fan in the bathroom .