they are for converting and applying the right amount of electricity to the bulbs. There are many different styles, brands, etc.. and are required for basically all types of high output lighting http://www.reefcentral.com/forums/showthread.php?threadid=550860
you can do that, but you would need to buy the reflector, bulbs, and ballast seperately or as a retrofit kit, still generally much cheaper than buying a pre-built fixture
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.