We don't color the joint material when setting bluestone. The setting bed material is used also for the joints which is a standard mortar. It'll dry a light gray color.

The joint on that stone is a bit wide and makes the the joint a bit more noticeable. We generally allow a 3/8" wide joint max.

Thanks, unfortunately they used a different color mortar than the setting mortar. The setting mortar is a gray that matches the stone well. Do you know if it’s possible to redo the grout? Or if there are products that can lighten the color?

Off topic, but what pool finish did you use? I love the color of your water! Would love to see the entire pool.

I like the look of the dark grout as it and it won't get dingy.