Blowing ballast and bulbs

I have an ongoing problem since I revamped my system. After 4 years I decided to go to the Lumatek 1000 ballasts and have had one blow already and 3 Hortilux bulbs blow also. The ballast blew about 4 weeks into bloom and the bulbs are blowing sporaticly. Now I have not changed anthing since I have started 4 years ago and may have had a bulb or two blow over the years. The ballast blew and tripped two 30 amp breakers so I assume there was a big problem internaly with the ballast. I replaced the ballast and all was good until today when another bulb blew. Everything is good for now but want to know if anyone else may have had or heard problems with these ballast.