Pulsing xenia dying off??

[acepumping]

hey, i have pulsing xenia using SOL blue led lights, they seem to be dying off,, a couple heads i had to cut off due to it becoming mush.
salinity 1.024
ph 8.2
nitrate 20ppm
nitrite ammonia 0
kh perfect
calcium 240


everything is good, in high flow near lights,
lights are 6 inch from water height
i dont know what else to do ?