Lighting info please advise....

Bulbs get warmer (look more yellow) over time. For a fish only tank you don't have to change them nearly as often as on a tank that needs light to grow. Think about what nature looks like as far as a day and go for that when you time your lights. Ie day time : full lights if you have the ability to dim your fixture remember that your lights like the sun should be at full power for 4 or so hours a day. If it's fish only it's up to you. Fish will adapt to almost any reasonable lighting pattern.

Heidi