Coraline doesnt like my rocks??!!

Hi Ive been trying to grow Purple coraline. It does grow on my tank, wavemakers and return nozzles but not on my rocks! The rocks Im using is the Carib Sea base rock. It was dry but Ive seeded it with booster plates from PSF and live rock, with no luck. Tank is about 1.5 yrs.

My reef veteran friend said my rocks are cichlid rocks!