Originally Posted by youngcam

All flexible grouts should work if the manufacturers instructions have been follwed.If they have then get them to send a rep out to look at it.
I normally use WEBER FLOOR GROUT and there AD FLEX ADMIX(think its called AD230)FOLLOW THE DIRECTIONS AND YOU``LL HAVE NO PROBLEMS.GROUT 4 TILE AT A TIME THEN WASH OFF THOROUGHLY.