t5 yes no...

[Stones]

I recently saw my first SPS/mixed reef tank lit soley by T5's and I was seriously impressed. The tank was lit by an 8 x 54 watt TEK fixture and all corals had amazing colours. Growth rates in his tank seemed to be on par with my tank however I too am using 2 x 250 watt MH as you are, but the T5 tank had much better colour. After seeing that setup, there is not a doubt in my mind that you can have a beautiful sps reef under pure T5 lighting.