Marginally off-topic. Not stealing your thread Lynne. But i'm using Micromax Cocoa at the moment and too be honest i hate it.
It's a nightmare to clean and really really gritty. Which made me think about your issue lynne. I'm just wondering wether there is too much "grit" and not enough colour pigment. Maybe the grey tones or colour you were experiencing was because of this perhaps?
But other than that it's also a real nightmare to clean. To actually grout the wall with it is like the krypton factor. Most ended up on the floor!
The travertine i'm grouting with it was a 305x305x 10 as well. Albeit, i#ve cut these in half so there's proberbly an extra 3 linear metres per square metre with what i'm doing. Now the bag states for this size of
tile, but at 9mm depth the coverage per 5Kg bag is 17.7sqm. Absolute tosh! I had to break into a second bag today to complete the wall i was doing. Meaning i've got coverage of around 6sqm for a 5Kg bag.
I'm seriously, seriously considering getting my pen and paper out and writing a letter of complaint.
Customer wanted the same colour in the main bathroom as well. 20sqm on walls, 4.5ish on floors. I've flat refused and offered them Weber brown instead.