[makana]

Are there any major appliances on the same breaker, (dishwasher, washing machine)?

It really sounds like either the ballasts are overheating or there are voltage level issues. A large draw will cause temporary voltage fluctuations. Hard to believe the ballasts wouldn't be able to handle it though.

Sorry I don't have better advice for you but I have seen "dirty power" destroy expensive electronics repeatadly while electricians and the hydro company both tested everything ok. The problem is most tests are only looking at the levels at that moment in time. I havn't heard if they where able to fix the problem once it was proven to exist.

I don't really know what I would do if I was in your position. The switch to LED may work, some sort of power filter or ups might help. You could call some local electricians to see if they have any advice or a voltage recorder to test over a longer period of time.

Good Luck!