White Grout gone blue

[Gazzer]

Well if the blue is on the surface then its not coming through the grout so it cant be a substrate issue. So more likely from the grout float, sponge, ink off the bag of grout etc etc.
When you clean a joint does the blue return ?

 

[Lukemac]

Bucket was yellow. just state the blue is not a dark blue. Its a light blue but u can definately see it is a shade of blue

 

[Gazzer]

Just for the record though, what was the condition of the substrate. If you can tell us step by step what you actually did and all materials then it may save us grasping at straws.

 

[Gazzer]

Have you any grout left. if so mix some up with clean tools and spread it over a tile. See if the blue is in the grout itself.

 

[Dan]

Has it fully cured? When was the grouting finished?

 

[kilty55]

was the grout well mixed?

 

[Stewart]

Sounds like efflorescence to me if it's a very light blue. As that's what it can look like on brilliant White grout.

 

[Lukemac]

I was very carefull when grouting this room as I once before had an issue with limestone drying darker in places. So since then I have been very aware off making sure I use a fresh sponge, clean bucket etc. The grout is now dry and Patchy and the blue does no clean of unless u scratch. It only seems to be on the surface. if scratch a couple mill down it is white. I used granfix flexi addhesive the grey one and was wondering if maybe I should use white, but I have been using this for the some time and never had this problem?

thanks again for any advice

 

[Lukemac]

yes stewart a light blue, like acrylic primer colour!

 

[ukProTile]

What tiles were they?