Personally, I leave lights off during cycling. I also cycle without sand. The only thing that is photosynthetic that you want in your tank at the cycling period is coralline algae. Coralline will bleach with no light, but it will come back in a few months. I think it's much more important to keep the tank dim (or even dark) during cycling since there will be an abundance of nutrients in the water column; add light to that and you get an algae bloom. If you're good at cycling, the only algae you will see in your tank will be diatoms and they will cycle out on their own. In fact, once the diatoms leave you should never see any other algae other than coralline in your tank, ever. Some people think hair algae is part of cycling, but that is only if you make mistakes (like adding light when there is still nitrate and phosphate in the water column). Hair algae should not be expected. Of course, we aren't perfect so we battle things like cyano, hair algae, and bubble algae throughout the tank's life. Argh!
