Hi Kristen! Sorry to hear that’s happening! Bath bombs can be quite finicky sometimes! Cracks are often a moisture level problem, stemming from too much or not enough liquid in the bath bomb. If your work area is too dry and warm, the bath bomb could dry too fast causing cracks. On the other hand, if the mixture was too wet when molding, it could cause cracks as it expands. Salt tends to absorb moisture from the air – is it really humid where you live? Or is it rainy on the days you’ve made the cracked bath bombs? If so, too much moisture could be a cause. One idea to try is to pop the bath bomb in the fridge to harden up and see if that makes a difference in cracking. Or, since you know it works well, you could try using the rose milk bath bomb recipe as a base formula, then change it up to make other kinds of bath bombs, using different colors and scents. I hope that helps and that future batches are better behaved! :)