I have the 20" 6 bulb version and it lights up my 16 x 16 x 20 tank great. SPS are growing nicely. I took some PAR measures with new bukbs the other day too:
(Old picture with new PAR numbers)
http://i290.photobucket.com/albums/l...07-07-09-1.jpg

Thanks! Thats great info.

And actually OA does carry the replacement bulbs. They are just labeled on the site as 20watt. But are actually the 18 watt.

This might be the best option. I don't think I am feeling brave enough to experiment with LED's! Not really planning sps either, so more than enough light for the one or two sps I will have.

i didn't mean replacement bulbs lol, i ment like high end bulbs (ati, AS, GE, KZ) no one makes bulbs in 20" but i guess i am just picky with bulbs choices

Yeah I knew what you meant. I would be picky too if this were a sps dominated tank but its not and I am trying to just keep things simple.

The last time I set this tank up it wasn't so simple and I hated dealing with it after a while, so I took it apart. I think T5's are the best way for me to go and this is the only 20" fixture I can find.

valid point. i owned this fixture before and it was ok. but like shimpchips posted it can still keep sps and does put out decent light.

one thing i hate about it was how load the fans are. besides that i guess its not bad for what your getting.