I did an Aqualight Pro mod which switched out the PC's for T5HO's. This really improved my lighting and I did it for probably less than what the MH mod would cost. Here is a link to thread...
http://www.canreef.com/vbulletin/showthread.php?t=40368
I had to pull out some pics as my photo quota was full but you will get the general idea. If I can help at all...let me know.