I grouted the table yesterday and all went well for the most part. I did my best to wipe off the excess grout on the tiles, without taking too much of the grout away. I was careful to use only a slightly damp sponge when cleaning it, because I know you aren't supposed to add more moisture back into the grout. This was actually my second attempt at grouting this table. I did it last year in the late summer/early fall and once the grout dried, it became cracked and flaky, not a hard solid like grout is supposed to be. I figured that the cracking had happened because I had either added too much water in the grout mixture or saturated it when cleaning off the grout. Or perhaps it was due to the longer drying time because of the colder fall weather.
This time I made sure to avoid those things. The weather is pretty warm right now here. I also made sure to have a very thick consistency when I mixed the grout. No cracking has appeared yet and everything looks pretty solid. However, when I went out this evening and took a barely moist sponge to the tile, there is still a lot of grout residue on the tile. The tile doesn't look super dirty, but the sponge came up gray from the grout. I'm worried that if I let the tile and grout dry much longer, the grout will dry on the tiles permanently. Is this normal? Is there a way to remove grout residue/haze after the grout has dried? What should I do?