ballast

[andniss]

I know this is probably been covered before, but it won't allow me to do a search on previous posts for some reason. What exactly does a electronic ballast do and how does it help in the lighting department.

[bertoni]

http://www.reeflightinginfo.arvixe.com/articles.htm

That link has pointers to articles on DIY setups of various types. They cover ballasts. The site has a lot of information on metal halide setups. What type of lighting were you considering?