what LED would you upgrade to if you where to upgrade ?ill start it off, i have used metal halides led and t5's.
i started off with metal halides when i first started. they put out a nice amount of light although my tank couldnt keep up with the heat. i also didn't like that i had very little attinic supplementation. i was running two 150w shopfitting units with 20k generic brand bulbs. i then moved onto cheap leds, i found the colours under the cheap leds were decent but certain corals didn't like it, when i changed tanks i moved to an 8xbulb 39w t5 unit. filled with ati bulbs. i have been getting great colours under this and its easy to change the colour temp just by changing one bulb. although i do miss the crisp light of the halides/led. also the t5's produce zero shimmer effect on the sand bed.
i do also have an illumimagic mc45 blaze led unit over my frag tank. coral colours are looking great under this the same as the t5's and the growth rate is also great. this is running off the same water as my display tank.
when i do eventualy upgrade to led it will be with a high quality unit but for now my t5's will do me fine.
rather then using t8's why not make a DIY strip of royal blue 3w crees. this is what i would love mixed in with my t5'sI am in the process of making a lighting unit for my 4ft, so far I have 2 150w MH with 14k globes and 2 blue led strip lights courtesy of Supercheap Auto.... $25 each and provide an awesome moon effect. Still undecided on flouro's maybe 2 Actinic T8 tubes and 2 white T8 marine tubes. Will also use cooling fans to extract heat from MH lamps.