XM 20K, do these get whiter over time?

[nlreefguy]

I used XM 20K's before and it is my experience that they do get a bit whiter over time (like all 20K bulbs, I imagine). But it is over a period of months that they get whiter and my experience was that it was still very bluish at the end of even a year of use (which I actually liked, but it's all personal preference). If my memory serves me, I think there is an article somewhere that shows that the XM 20K bulbs have really low PAR compared to the 14 or 10K and even low par compared to other 20K bulbs, though. (maybe it's on advanced aquarist or sanjay's site).