I'm a huge MH fan, but I have to say that T5's are awesome. Recently, a friend of mine (Canuckgod420) changed his 250 w halides out for an eight bulb t5 fixture. His fixture isn't the highest quality available, but it grew his SPS way better than his halides did. He was running expensive shades with top end bulbs too. If I had the choice, I would go with the T5's. The growth is fast, colours are more vibrant and you have way more control over the colour of bulb that you want to run.
Don't worry about your SPS, they will grow better and faster than ever
. Good Luck!!
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90 gal SPS display+65 gallon mixed reef
GEAR: Korallin calcium reactor, bio pellets, digital aquatics controller, Tunze ATO, MP40, 4 x Tunze 6105 w/controller, Reef Octopus Xp3000 ext, 2x250w MH, Futura LED.