7Speed,
I agree with slipknottin it would work for low light and some medium but very risky for anything else. The skylight glass and angle is going to cut down your spectrum the other glass top is going to also. We worry about enough light with the bulbs inches to a foot above tanks imagine how much your light is going to have to get through. With sunlight you get unwanted heat and tempature swings. Slipknottin said the winter is going to a problem so will rainy days or when there is snow if you get it and there is no light coming thru when covered. i personally would not try this unless i could get a minimum of 10 hours of (good) lighting year round and had some kind of good backup lighting. Some places that our corals, anemones and such come from have 12 hours or more of light during the summer and nothing to block it other than water. The other point is when are you going to enjoy it in the morning only this would suck if i had to do all my maintenance and observation during a 7 or 8 hour period. I guess you could look into it futher the large coral farm i go to is mostly lit buy sunlight but it is a giant greenhouse and they have halides over the corals that need intense light.