the xm 20k is a very popular bulb. most say it gives corals some of the best color out there, radium may be a little less blue and corals may not have quite the color, but they grow a little faster bc of higher par... you gain one place, but lose another, it is a trade off but both bulbs are great to me. do a review of the xm so we can know for sure
I like our radium at the store, but for color it could possibly be a little bluer, i don't really like the phoenix bulb for example bc it only really has the color blue in it no other wavelength... you only see green and pastel everything else, where the radium seems to make everything purple. I like t5 bc you can combine so many colors and enjoy the best of both worlds (fluorescence and pigmentation) but you don't get the shimmer there is a trade off in anything eh? sorry for rambling
