what temp. do you want it to be in your 150 gallon tank? if you have the right heater(s) for your application, you would set it for whatever temp you wanted it to be, and then double check it with a thermometer. :wink:
my tank never leaves 80 degrees but i think people are looking to keep it at 78. what kind of lighting do you have? where do you live? use air conditioning? I keep my tank in my basement and temp never changes down there at all. it is easy for me to regulate it I think the most I ever saw it was at 82. a lil high but normally it is at 80 even.
i have not done the lighting yet i just have the normal white lights i am doing things step by step. it's directly in my living room and the temp in the house ranges from 74-77 depending on who's home.
you should be good get a heater set it a little highter, monitor it get a thermometer and set it at 78, not much more too it, you don't have a big heat source with the lighting, no worries, get er' done