I have a 4'x2'x16" tank. It is currently a mixed reef about 7 months old. I would like to get into more SPS in the future. I currently have 2 radion XR15 blue gen5. My question is; would it be better to get another radion xr15 or add 2 AI blades? looking to decrease shadowing as well as keep SPS. Will a 3rd radion decrease shadowing? Thanks for your input