Light period

[ogopogo]

Hey guy's, I was just wondering what the ideal time to be running my lights would be?
I will tell you the details of my tank,
Its a 55 gallon display tank, with a 25 gallon sump, 55 pounds of live rock, and 40 pound of live sand, with a Coralife superskimmer 125. Im going to be running a sump light for either chaeto or more then likley mangroves because I really want to try those out. And my main tank's light is a 250watt hamilton 14K.
How long do you think I should let the display tanks light run for?
Thanks guys!