D
Dumbo
Adhesive manufacturers always blame everybody but themselves I grouted a limestone floor with bal limestone grout it came out grey they claimed their was nothing wrong and it was in their colour spectrum for grey grout . Also very little help from Topps tiles who sold it to me .All details were posted on this forum.
Basically left dark patches on the stone looking like moisture staining.
Was an easy fix eventually with simple Grimex clean down, but after Ultra visited site, blamed everything apart from their adhesive, and left my customer with no confidence in their abilities.
Simple rule of thumb when fixing light coloured limestone is use rapid.