The four bulbs that are in the fixture currently are actinic bulbs (for coral growth). You can swap them out for other T5HO bulbs for freshwater tanks. There will be some discrepancies between which combo you actually need, but bulbs around 6,700K aren't bad.
Ok so would any t5 bulb work as far wattage when switching bulbs in a t5 light fixture? Im want to make sure I don't put a wrong t5 in there and destroy the ballast if that is even possible.