Ya aluminum foil is a bad bad bad very bad decision...speaking from experience. i had so many people and videos say never to use aluminum foil as a reflector for growing. I didn't listen.
so from an empty file cabinet I constructed my grow room using t8 fluros warm white and cool white.
Covered the walls with our reynolds wrap foil and within a few days started noticing discoloration in the leaves.
Which is from the bends and different inperfections I had made inthe foil. It focuses light on different places on the leaves. take a magnifing glass to a plant in the sun and burn the leaf. If you dont get you foil completly smooth...(let me know if your able to pull that one off) this is what it will do to your leaves...
hope that helps man, i may be wrong cuz I am kinda new myself.
if any one thinks other wise let me know. peace