How do I get rid of this on the grout?

[kkudi]

I've tried baking soda, white vinegar, baking soda with white vinegar, Flash with bleach, Cillit Bang Cleaner, and HG Grout cleaner. It doesn't seem to go away!

It's a fairly new bathroom and would like to keep it as clean as possible, and this is driving me nuts!

Photo here

Please help!

The grout is Micromax Smoke from Topps Tiles and is meant to be efflorescent free!

It has also started cropping up in other random places on the 'shampoo box', only at the bottom. When we shower we make we remove all excess water and we wipe it down too.

I suggesting contacting Topps Tiles for advice.

Anyone else any thoughts?

I sent them an email last night but do not expect much from them to be honest.

no one has any thoughts?

Without being able to touch the grout.. Here is a thought: could it be that the rule adhesive mortar was left to rise between the tires and wasn't cleaned up properly during installation. Then a thin layer of grout was applied over it while the rest of the spacings fit the proper full depth.
Cleaning products tend to eat through the grout, so where the layer was super thin (consistent with entry or nook as they are the more difficult areas to finish properly), it was removed through cleaning.
I suggest you get a tile grout scraper, or simply a trade knife and scrape the light surface to see if it comes off and what is left behind it.
If it is mortar after all, then easy to fix.

I think that looks like the adhesive as the pp has said.

it does indeed look like it's the adhesive. any thoughts as to how to fix this?

Scrape it off, regrout?