I've upgraded earlier this year to a 220 gal when we moved. Ran 3 16" sbreef over it with somewhat lackluster results. Everything lived but not really growing very quickly. Plan was to add T5 supplements to the sbreef but I had a halide hood. I've kind of decided to go back to 250w halide and thinking now either t5 or led supplement. Would 2 80w t5 have any affect? Led options are reefbrite, sbar orphek bar I guess?
That will depend on how long you will leave your halides ON.
Supplementing the halides with the T5s is not a big of a deal at all IMHO.
Back in the day I had 2 X 250W halides with only 2 T8s for supplementation over a 125gal. You can do that easily with T5s even if you want to keep mostly SPS and they will not only look amazing but will grow nicely!
Get a Vornado or similar fan to blow heat from halides placing the fan between the fixture/pendants/ and water surface.
Choosing the number and spectrum of the T5s will depend on what you're going to keep, how long you will leave the halides ON, and the halides' spectrum you choose.
If you get 4 T5s you could leave the halides OFF for a little longer. One compensates the other... common sense. All good! Easy and safe!
Could start with 2 T5s for supplementation and add 2 more in the future, if you want.
I have 2 X 250W Radiums with 4 T5s over my new 75gal zoa system. The T5s are ON longer than the halides are. It would be a big difference if I had LEDs instead.
The beauty of T5s is the uniform light they emit and different bulbs' spectrum available. You'll have the ability of changing them any time you want ,with the many choices available. I like ATI Blue Plus a lot!! I'm using the Giesemann Actinic Plus with the Spectra over the new system now and it's a great bulb too!!
Your tank will be amazing with the halide/T5s! That's for sure!
My personal opinion.