I've just tiled my bathroom and started grouting tonight with Bal micromax gunmetal. The grouts been down approx. 4 hours and looks to be drying very patchy colour wise. Most of it looks to be drying fairly light, while some smaller areas are a totally different shade. Granted, I appreciate it won't have dried properly yet but I'm worried that I've ballsed it up. Admittedly, I wasn't mixing consistently by weighing and measuring. I was just mixing batches till it looked and felt the right consistency. I also suspect when sponging down, the sponge was probably too wet... Could I have sabotaged myself by doing these things? And if so, what are the possible ways to fix?