Lights can be frustraiting !!!! I went through exactly what you are going through a while ago.
We need some info to help you out...
What are the dimesions of your tank???
What fixtures do you have now??
Do you have live plants??
What is your budget???
What kind of hood do you have on the tank and how much room do you have for lights???
On my 55 I have 4 light fixtures. 2 6500k tubes to keep the plants Happy, and 2 8000K to make it bright and make me happy
On my 125 long I have a 72" fixture with 2 tubes, 3 metal halides and some blue LEDs for night time viewing.
Let us know what you are working with.... Post a pic if you can