Sps color and radion

[Proteus]

I've been struggling with some color in my tank.
My red planet is yellow while others like my deswalli are great
Pink Floyd is green and not gaining any color

I have a 24x24x12 half cube. 90% of coral is 6" deep. The radion(gen1)is 10" above water. It starts at 3pm ramp for one hour to 10k at 70% going to 20k @ 80% by 10pm ramping down for 1 hour
I feed very little as I only have three chromis. The bioload is very light with skimmer only pulling after dosing coral snow. It's a prodibio tank


My params

Nitrate 0
Po4 undetectable
Ph who knows

Cal 450
Alk 7
Mg 1350/1400

I'm on the verge of buying a 250w metal halide but thought some gurus may have suggestions

Much appreciated.