BB tank and lights

[MO3N]

i recently got 7 discus soon to be ten that i am growing out in a 75 gallon bb tank. the tank will be planted once they are full grown. i have a piece of driftwood that has alot of plants tied to it and i want to keep these alive with a light over the tank. but the light i have is a 24 in CF light and when i turned it on the reflection from the bottom scared the fish into hiding.

my question is should i run the light and just let them get used to is or should i put some sand or somthing else on the bottom under the light to make the reflection less?

thanks for the help.