I just got a PAR meter, and measured the output from my T5 setup - the daylight bulbs put out 600-700 mE/m2s, and about 400-500 from the blues and actinics.
About 6" underwater I am getting 300-450, 12" about 240-360 and 24" under I am getting 120 - 200.
SPS and clams are doing well (even though Tridacnas should in theory have more light) but this is not as bright as 250 or 400 W MH setups. Some 175 MH setups are in this range.
Not sure how you would use a T5 setup on a 10 g tank anyway - the smallest setup from Sunlight is 24".
Anyone else have PAR readings to compare? I have seen this article below -
http://www.advancedaquarist.com/issu...03/feature.htm
I bought T5s because I did not want heat, or fan noise in the room - and, a lot less electricity consumed. But, the bulb life I have had is a lot less than advertised, and they cost too much.
When I put in my dream tanks, I would go big with lights. But, for a quiet setup, T5s are nice.