AI questions, I am considering wether to get them or not.

3 would be fine for your 125. Generally you want one for every 2 ft, so 6 ft tank you'll want 3. I think they're very worth the money, if you think about how much you'll spend on bulbs, t5's or hqi's, the units will pay for themselves within a few years. I've found from adjusting mine, 12-14" gave me a good spread on my 75. I'm upgrading to a 180, along with adding 2 40 breeders for frag tanks, and a quarantine. I'll have AIs over all tanks, 6 units total. I absolutely love them.

 

I like mine. I am satisfied with the growth although I do feel 1 or 2 t5 bulbs would make a nice touch for my viewing pleasure.

 

How many did you add? I was thinking 2 1 being a fiji pink bulb

 

I don't think 3 would cut it unless you mount them high like 12"+ I would go four especially if you plan on keeping sps

 

I think 4 would be overkill. 125 is same blueprint as a 75 but 2 ft longer. I have 2 over my 75 and keep everything including a lot of sps, all very happy.

 

For what it's worth I tried hanging a single SOL over my cube which is 24"x24" it looked hideous! It had a really fake shimmer look and tons of shadows. After adding a second one it looked comparable to the 250 watt MH I previously had hanging above the tank.

I would put ATLEAST 4 on a 125 if your wanting to do a lot of SPS.

 

I agree with the 4. Im not happy with them yet. Ive had them 4 months and my mh did so much better. I wished I would have stuck with mh.

 

RayI have three over my 200g corner pentagon.  They're mounted 12" above the water.  At peak they run 80% Royal, 65% White, and 60% Blue.  They easily grow corals over an area over 50" long by 24" wide.  My tank is bigger around than this, but it was my intention not to light the sand in the front of the tank or the corner overflow that's 42" from the front.I couldn't be happier with them at this point (been about 6 months).  Some of the SPS started to turn green when I first switched over...but now they're all getting their original color back and more.  The growth has been greater  than my old 6 bulb T5 setup. I run the stock lenses (70 degree lenses on the outsides and 40 degree on the insides).  They have no problem growing encrusting Montis on the sand even at 36" from the lamps.My photo period starts at 8am with a 4 hour ramp up, stays on high until 5pm, and then a 4 hour ramp down.  I immediately saw the electric bill drop $10 per month and it's nice knowing there are no bulbs to replace.  
At worst, be prepared for some color shift in your corals.  Patience is the key.  IF they change, they will come back.  There are too many knee jerk reactions to reef keeping.  If you get them, wait it out and good things will happen. Jeff