I was wondering (a bad thing to do It cost me money) I have a vho lighting system in my tank 640 watts total. This tank is a fish only tank with about 280 pounds of live rock. Would it be practicle for me to switch to mh? I am an electrian and have an ample supply of vho ballast(free) just wondering. Another thing to consider when or if you diy mh the bulb will have ansi standard number on it match it to the proper magnetic ballast and their should not be any problems. As far as electronic ballast I have little practilce, I do understandn the tuning issues. But if you remote mount ballast the old fashion mags would do with proper venting . thanks blammotor