Haven't done it, but I don't see why it couldn't work from a PAR perspective. If you want to match the new LEDs to your T5's output, that'll take some research obviously. However, you might want them to have different PAR performance so you can have different types of corals at different levels on the ends of your tank. You also need to think about color spectrum and shimmer. Regarding the former, you'd want LEDs that you could program to match the color look of your T5 if, I assume, you don't want the middle of your tank to have a different color than the ends. For shimmer, same appearance consideration...although I don't think one can adjust shimmer on LEDs, but I don't know. Finally, regarding how the lights themselves will look paired together, I don't know. I'm assuming your current light is visible from the front of the tank (ie not hidden by a canopy, etc.). In my opinion, using minimalist hanging hardware so that lights appear to be almost free floating above the tank looks cool. I imagine doing that with two LEDs on each end with a T5 in the middle would look cool even though all three lights don't match because it would still be a symmetrical arrangement. HTH. Have Fun!