Marineland LED lighting

I do believe the AI sol would cover a 40B, it would just need to be mounted high enough for the proper coverage. It would be most definitely capable of sps.

 

Yeah, maybe you could keep SPS directly under the AI sol, they wouldn't do well in much of the tank with just 1.

You may be able to keep SPS alive with 100 PAR, but if you want them to actually thrive, you need to get close to their photosaturation point.
From table 1 at the bottom of this article, the photosaturation point for most acros and other SPS is around 300 PAR....

http://www.advancedaquarist.com/2007/3/aafeature1

From here, Sanjay tested the AI SOL:
Feature Article: LED Lighting Tests: Aquaillumination, Blue Moon, Eco-Lamp KR-91, Ecoxotic Panorama — Advanced Aquarist's Online Magazine

We can see that even raised 24" off the bottom, the area covered with 300 PAR is only a measly 6 inches. The area with 100PAR, the minimum for SPS to live (although they will likely become pretty brown if truly kept at 100 PAR) is only 24 inches. Rased higher, the 100PAR circle and 300PAR circle is even smaller. His tank is 36".

I mentioned the Boost LED. That will give much better spread and cover the tank for a lot less. On a 40B, you should be able to get 300 PAR for much of the tank and easily over 100 PAR for all of it.

There are also some cheap chinese lights such as the EVO lights sold by Reef Koi. These seem to be getting better, now with the bridgelux LEDs and dimmer controls. Also, you could do an DIY kit. There is another company E-shine which makes really cheap chinese leds, but good luck with any warranty problems. Reef Koi is a company out of Colorodo that at least warranties their lights for two years and does their own repairs. Appollo makes good lights, but they are not dimmable yet and have more focused optics than the AIs, so they will not cover your tank with one and 2, without being able to dim them will fry your corals.

Other than that, the next just up is into the $800+ range or lights that will not sustain your corals. I'd go with the boost Mu 135. It really is a good fit for your tank, reasonably priced and good quality.

 

Kessil a150w for about 300$ are a great choice for LED I have the 10k and plan on getting another soon, check them out you won't be dissapointed