The extreme heat can make succulents more susceptible to sunburn. In areas like the Southwest United States you will need to protect your succulent from the afternoon sunlight during the summer. If you need to use a rooting aid, try to repot the plant into separate containers so that the chemicals aren't transferred to plants that don't need them. The amount of light you use and the plants you have will affect how many plants can you keep under your grow lights. Remember that you're caring for two plants at once.