Grey grout, matt white subway tiles...Staining?

[Rabbit Chef]

I've completed some matt white subway tiling in my bathroom and have started to do some of the grouting.

I've done one area of about 1sqm using Ardex FS grout in Ocean Grey colour. I'm unsure as to whether I should have sealed the matt subway tiles prior to using this grout.

The grouting doesn't appear to have caused any staining apart from small areas on a couple of tiles where there is some very faint grey stain. I don't know why it has only occurred in these couple of places as I grouted and cleaned the whole area in the same fashion.

I don't want to carry on unless I can prevent this happening worse in other areas.

Should I use some sort of sealer on the tiles before grouting any further?

Does the sealer affect the final sheen of matt white subway tiles?

Can I remove the small area of mild staining as I'm a bit of a perfectionist? I have some HG Limex somewhere if that's of any use.

Thanks for any help

 

[Bill]

photos please

 

[J Sid]

does it say on box not to use dark grout ?

 

[Flintstone]

 

[Rabbit Chef]

Thanks for the reply.
There's nothing on the box about avoiding dark grout.
It's impossible to photo the problem but it's on 2 of the top line of tiles. It just looks like a very faint dirty make on part of the tile surface. It's not that bad, but I don't want to carry on as I am and it be worse in other areas if there's something I can do to avoid it.

 

[WetSaw]

Might be just a bit of haze from the grout. Try some Fila Deterdek or similar.

 

[Bill]

Have you polished the grout dust off?

 

[Rabbit Chef]

I've been over it with a damp sponge and then a dry microfibre towel

 

[Flintstone]

Give it a good clean down with a damp microfibre cloth and see how that goes. Failing that, try a grout haze / residue remover

 

[Rabbit Chef]

Will do. Thanks