I figured I'd chime in because I also have a 150g tall with the same dimensions (48x24x30).
I have two xr30 Gen2 Pro's with narrow lenses, 4x T5, and a LED bar that is 48x 3w LED (supposed to add 100 PAR at 18"). My rock structure is very low and this tank is SPS only. I have a lot of Acros growing in here, including at the bottom. Up to this point I've had good luck with the Radions, but now that the corals are getting bigger I think I am going to have to add more Radions.
I have never taken a PAR measurement, but I am guessing its around 200ish at 30" depth due to the response from the Acros.
The Gen4's you are looking at will have better spread than the narrow TiR's I am running, but probably less PAR at depth. You would probably be best off in the short term by maximizing the spread and going with 4x XR15 model, but long term you will probably need more. I will likely end up with 4x XR30's PLUS the T5 and LEd bar. Without full coverage from supplemental lights the Radions WILL shade and when your frags get big enough they will not be getting the light dispersal they need. Every person and shop I know that has truly "nice" SPS with LED only is doing it with more fixtures than most people are willing to pay for. That's the reality with LED.
If you are intent on just having LED fixtures for high light inhabitants, you might want to consider 2x AP700 or 4x XR30 pro. From what I've seen with my own eyes a single AP700 is better than 2x kessil 360. Or if you are willing to mix lights, then 2x XR30 pro and 4x T5 should give you what you need (at least for quite a while).
Hope that helps,
Ed
I have two xr30 Gen2 Pro's with narrow lenses, 4x T5, and a LED bar that is 48x 3w LED (supposed to add 100 PAR at 18"). My rock structure is very low and this tank is SPS only. I have a lot of Acros growing in here, including at the bottom. Up to this point I've had good luck with the Radions, but now that the corals are getting bigger I think I am going to have to add more Radions.
I have never taken a PAR measurement, but I am guessing its around 200ish at 30" depth due to the response from the Acros.
The Gen4's you are looking at will have better spread than the narrow TiR's I am running, but probably less PAR at depth. You would probably be best off in the short term by maximizing the spread and going with 4x XR15 model, but long term you will probably need more. I will likely end up with 4x XR30's PLUS the T5 and LEd bar. Without full coverage from supplemental lights the Radions WILL shade and when your frags get big enough they will not be getting the light dispersal they need. Every person and shop I know that has truly "nice" SPS with LED only is doing it with more fixtures than most people are willing to pay for. That's the reality with LED.
If you are intent on just having LED fixtures for high light inhabitants, you might want to consider 2x AP700 or 4x XR30 pro. From what I've seen with my own eyes a single AP700 is better than 2x kessil 360. Or if you are willing to mix lights, then 2x XR30 pro and 4x T5 should give you what you need (at least for quite a while).
Hope that helps,
Ed
In fact, I even carry some WWC sps and have grown them under both Mars Aqua and Radions. The Mars Aqua will "grow" them sure. But the Radions have better spectrum and higher par and the coral will grow faster and usually with better color in my experience. The OP also didn't mention how tall their rockscaping will be or how deep they want to have SPS. The radion will give him the ability to grow a wider variety of sps deeper in the tank than the Mars Aqua.
