If the LED fixture are made with the low current LEDs, eg. 3mm, 5mm, even 10mm, you can basically forget about it. Don't even waste your money buying them, even if they are cheap. They just don't put out enough lumens to begin with, even if you spaced them densely.
Showing someone a tank full of corals "not dying" under low power LEDs simply proves nothing. I have seen people growing all kinds of acros under CF lights, with great color and growth also. Does it mean everybody can grow acros under CF? Of course not, you have to be experienced and a bit of lucky to get that kind of success. If you don't have those, it's better just to follow the bandwagon.
High power LEDs like the ones Solaris is using might have a future, especially couple new model of high powered LED just got on the market. These newest model can put out 600+ lm @ 700mA from only one single LED. Just to give you a comparison, a regular high brightness 5mm LED that similar to Exotic is using in their fixture only averagely puts out 1.2 lm @ 20mA.
Buying Solaris right now is a bit waste of money also, because the technology changes everyday. Newer and cheaper high power LED keep coming out. It's almost like buying a computer, if you pay $2k for your computer today, it might only cost $500 half a year later. That is also the reason why Solaris discontinued their older fixture and they are coming out with new ones with newer LEDs. I feel bad for the people who shelled out $4k for theirs just last year, becuase those doesn't worth anything anymore.
Another option if you want to save a bit of electricity is DIY. Average cost of each high powered LEDs are around $5, cheaper if buy in bulk, these are around 210 lm @ 1A and about $20 for the newest high powered ones I mentioned earlier. You can space them out like you see on the Solaris units. i.e. around 25 LEDs for lighting approx 1'x1' area. So for a 3' tank you need approx 75+ LEDs, that is around $375 in LEDs. Plus LED drivers, heatsink, fans, etc., you will be looking around $500 at least. Also each of these LEDs are approx 4W each, so for 75+ LEDs, that's equal to 300W already, not too far away from MH + T5 actinic.
To sum up, it's not only about the light you are using, that just contributes a little part of the whole equation. Spend some more money and time on better skimmer and maintanence will probably get you better result. LEDs are the future no doubt, but it's still a bit expensive right now, just wait 3-5 years, it will change. I have nothing against LEDs, actually I am building one myself with PIC controlled right now. Should be finished soon, I will give more data when it done, so stay tuned
