hey im tryin to save as much money as i can to put into rock and corals and things like that. im only fourteen so i really dont get a high amount of money a week. i'm wondering if instead of buying a expensive four tube lighting fixture wit the timer and all that fancy stuff if i can just buy two doubles. i have one that my cuz gve me from his old tank and i was wondering if i can but a smaller one in . my tank is 36 inches long and i hve a 36" t5 light on it now but i want another light to put a actinic tube and a regular tube in the other one. can i get a 30 inch light or do i need to get another 36" one. any advice would b very helpful. -thanks