Which tank is this for?
Color temperature is not the same as light output.
Either of the bulbs you have should work fine. If the flora sun bulbs look nicer, use them. That brand is sold as 32W bulbs instead of 40W. I don't know if there is actually any difference; standard 4 foot T8 bulbs are 32W, but most aquarium T8 bulbs are 40W.
6500k daylight bulbs from Lowes are $7 for 2, they look good and should work fine if you don't want to spend 4x as much in the future at the fish store.
Color temperature is not the same as light output.
Either of the bulbs you have should work fine. If the flora sun bulbs look nicer, use them. That brand is sold as 32W bulbs instead of 40W. I don't know if there is actually any difference; standard 4 foot T8 bulbs are 32W, but most aquarium T8 bulbs are 40W.
6500k daylight bulbs from Lowes are $7 for 2, they look good and should work fine if you don't want to spend 4x as much in the future at the fish store.
