What type of timer are you using? I use a T-104 timer it can handle upto 8 ballast at once. You probably wired your ballast wrong or you have fried your timer. Easyiest thing to do if you dont know how to wire ballast is take it to a local hydro store. Get them to wire it.

Quote Originally Posted by harris7
interesting. I had my light timer between my ballast and bulb for a little while. now it dosn't work. could the current (240v) have fried it?