Not sure if petsmart is making a mistake but they have a 20% off anything online plus buy one get one 50% off on caribsea liferock dry live rock. https://www.petsmart.com/fish/decor...es/caribsea-liferock-dry-live-rock-64745.html.
If you get TWO boxes that's about 40% off total.
If you get TWO boxes that's about 40% off total.