[leveldrummer]

people actually light reefs with natural sun, if you practice proper husbandry, keep your nitrates and phosphates very low, it doesnt matter how much light you poor into it, algae wont be a problem, especially after you toss in a few snails and hermits. heat will be an issue, but not that much of one. i wouldnt put it directly under a window that faces south, that gets 9 hours of solid sunlight through the day, but in the same room is fine. everyone is really getting too worked up about this question, yes, putting it across from a window is fine. putting it right infront of a window is fine too, if you have blinds or curtains, you wont have any issues at all.