I have a 6 bulb tek light like to figure the proper height and length of time to run them each day. I have a4 blue+ and coral+and a purple + my tank is 27" deep
i run my t5's about 9 inches off the water. i run my blue lights for 9 hours and my white lights for 6. some do more then that like 12 and 10 or something like that but i mainly have lps and dont really care if the corals in my display grow crazy. in fact the lights dont even turn on until 2:00 in afternoon.