The area is only 1.5sqm. So I only mixed a small amount of grout. I normally use BAL grout, but recently customers have been getting their own grout. I did 30sqm of floor a few weeks back and used an Italian grout. I mixed it to the letter (used a measuring jug for water). It turned out so dry I had difficulty working with it. I have never used Granfix grout, but it did state only to mix enough for 20mins work! Good job I was not doing a big floor area, as I'm pretty sure there would definitely be colour variation in the grout. So if anything, I may have slightly (only slightly) mixed the grout a little on the wet side. I used a well squeezed out sponge to wipe off excess grout. If I don't have any luck with the vinegar do you think I could just paint on Aquamix colourant?