I currently have a single strip fixture for my 90g fowler with a coralife 50/50 bulb.
The fixture is aging and I'll probably replace it soon.
Would a double strip better? If so, what combination of bulbs would work best.
Again, it's a fowler system so no corals.
Since it's a FOWLR, lighting makes no difference except for how the tank looks to your eye. For a double strip, 1 65k daylight and 1 actinic works nice, or for a little more blue look you can go with a 10k and actinic.