Seems like another thing to remember is stress. I don't care much for it myself but sometimes it's a good thing.... Like the stress in the stalk caused by a GENTLE breeze from your fan. Yep, makes your plant release a hormone that helps in strengthing your plant's stems so they grow up big and stong! Ain't that cool... Plus the fan keeps all that fresh air and CO2 (?) moving around. Now don't get me wrong, it WAS the (lack of) light more than anything but, next time, this will probably help too..........