Is 2X39 W T-5 bulbs over a tank low light ?

[PattersM]

Looking to set up a 3ft tank for low light loving creatures. Thinking of some yellow sun corals, gorgonians and scallops.

Is this amount of light low enough to be thought of as low light? The tank is 18 inches deep but is acrylic with an acrylic top.

Also will the fish care about the light level?

It will be eventually plumbed into my existing 55 gallon that's been up over a year so was planning on base rock to landscape so won't be expecting a cycle.

[duncaholic]

expect a cycle! it will happen. Sun corals are not photosynthetic and don't need any light, so I would suggest putting them under a rock ledge, or they likely won't come out during the day (even in the shade they probably still won't comeout during the day). No experience with gorgonians, but I've always found scallops difficult to keep. They are filter feeders that require some source of tiny food like phytoplankton, and they will move which I find annoying. Generally "low light" corals will do well in lower light condition, but my experience is that they will do even better under more intense lighting. Just look at what they are under when you buy them and make sure that if your lighting is more intense that you acclimate them with shade cloth and shorter photo periods, as they can bleach with a sudden increasein lighting, but 78 watts of t5 shouldn't be enough to hurt anything.