I am using workhorse ballast with Geismann bulbs. I have used only 4 and supplemented with 250w MH. However, if I can get the color spectrums adjusted, I plan on replacing the MH with LED (cool white, warm white, red, and royal blue crees). I would be interested in seeing the 'before' and 'after' PAR ratings. I love the look of T5 and MH, but I do not like the PAR inconsistency and the burn out over the course of a year. If coloration can be improved, perha[s LED will offer more stability.