Our pool was finished April, 2018. This summer I've noticed some cracking in the grout along the top of the waterline tile. The coping is travertine. Attached is a pic of the worst spot. There are areas where there is no cracking at all, and areas where it's barely visible. Is this something to be concerned about or that I need to fill, or just don't worry about it? Water only gets up this high if we're having a downpour that the overflow can't keep up with and I can't pump out fast enough. Which does happen occasionally. As always, thank y'all for your help!
