hey wait a mini think i see two reefs in background,and no pic'slol ,to be honest i run and love bare bottom tanks,never painted one ,just a thought here ,black absorbs light ,will it cover in algae too fast?? white will reflect light again ,will it cause problems?? i don't have that answer ,but think something to think about,once done,too late.????beige like beach sand,lighter blue ???just suggetions ,never did ,mine were all pink..lol ,foam insulation board