i was looking at the 48-60" and was wondering if it had enough power to keep sps and clams in my new 120 when it goes up? the 120 is 48x24x24 so i would get the 48" and i beleive it will have 54 LED's. But i was told the 1w LED's may not be strong enough. here is the ad/article-
that fixture is pretty bad, there are currently no 1W LEDs that come anywhere near the efficacy of the current high-power 3W LEDs. 64 PAR directly beneath the fixture at 24" deep is pretty bad... notice also that they do not indicate those are PAR numbers in or outside of water based on what ive seen from the number of 1W LEDs you need to get those numbers, that is not a through-water measurement.
for your 120, you'd probably need at least three of the 48" fixtures. Notice on the picture it even says "depending on your illumination needs, multiple fixtures may be required". This would get you to a point of lighting the entire bottom, but you may need a fourth to properly light all of the water surface based on the beam pattern they are showing.
Based on what you said you wanted to keep in chat, you could probably get two AI units and have them put all 70 degree pucks in them and light the tank a lot better for the same $$ as the marineland units would.
or you could DIY and do it even cheaper, if you're willing to put in the time.
If you want to stick with LED, and don't want to build, then maybe something from Acan Lighting, or Maxspect. I like the Acan Lighting fixtures more than the Maxspects, but they are more expensive. As XSiVE mentioned, AI modules are also an option, but I don't think a pair of them, even with the 70 degree lenses, would cover the tank effectively.