Sorry I'm kinda confused, acclimate them to the substrate or to the water?
In case you are in a rush for this info I will answer this one for you.
Burbon means the water, some substrates can alter the water chemistry, coral gravel\sand being a prime example. Try and use a substrate that is inert (doesn't alter the make up of the water). Most aquarium sands and gravels are generally fine....just ask before purchasing.