I was wandering which is best & why when it comes to balsts
1. What is a magnetic balast & how does it compare to an electronic, tar, or cold pac balast?

Welcome to TR.

Icecap is prolly the best brand to buy for ballasts.
Electronic ballasts are supposed to be more energy efficient.

^^ BUMP ^^

http://www.talkingreef.com/forums/podcast-episodes/2623-lighting-part-3-metal-halide-podcast-episode-77-a.html

I forget all the details that were in it, but I think in this episode Rob covered some of the different types of MH ballasts so check that if you havent listened yet.