New white grout - orange in patches

Hi I agree with the guy from excel Tiling, I never would use a ready mixed adhesive tiling on tiles. I would all ways a good quality powder adhesive which is slow set and is much stronger, I leave the grouting 2/3 days depending on time scales for the job. All ways use a good quality grout for a shower area which should be mixed properly .

I have had the same problem before.I found that grouting to early ie the day after with ready mixed product can cause on occasions discolouration.Mainly due to the fact that the grout can mix with the adhesive when not fully dry and causes the adhesive to bleed into the grout.i would have left the adhesive 48 hours as tile on tile takes longer to dry.Im aware blue star is white however if not fully dry it could still cause discolouring.I normally use powdered slow set adhesive which dries like concrete rather than a bal product which doesn't tend to dry as efficiently.I no a few tilers who wont used ready mixed on any tiling due to this.Also it can depend on how you mix the grout,how you apply it and how you clean it off however the only times i have had a problem is when i have grouted to early. Kind regards Rob EXCEL TILING.