Hi Gerrard, The water perimeter play an important role for the clam
development and they will thrive if the water temp are low. I have
2 crocea and one big maxima with my undetectable No2, No3, Po4 with
water temp at 25-28 degree and ofcause 3x250W mh.
Like other bro said with your setting you can move it up to mid-level
and check your water perimeter to correct it slowly.