A recent posting on the ON4KST 6m Chat page brought up the question of QRN coming from fluorescent lighting.
Lefty, K1TOL, had a lot of QRN coming from his neighbour's garage, about 1,000 feet away. He solved the problem by changing the ballasts, purchased at Home Depot. This is the ballast that solved his problem, so if you are having similar difficulty, perhaps this will be of benefit.
Sometimes just changing to a different bulb type (manufacturer) will solve the problem as well but from what I have read, you get what you pay for and likely the bargain-bin bulbs are not the quietest.