Grout changing colours

[Gazzac23]

Have few small issues with grout. Using mapei ultra colour plus which is light grey when white but turns to a dirty brown when wet . It's in a wet area.
Is there any alternatives to keep the grout a light grey by using a sealer or is that a stupid question?
Or any other grouts out there someone knows of that hold there colour when wet?
Thanks

 

[Flintstone]

Only epoxy grout does not change colour when wet as it is none absorbent, all cement based grouts are porous. A sealer may help but not like an epoxy and not permanent.