New fluorescent lights probably have electronic ballasts, which can generate a LOT of noise. The fix is to put a X10 filter in-line between the switch and the lights. Depending on the total current drawn by the lights, you could use either the 5 amp Leviton 6287 or the 20 amp X10 XPF. Note that the XPF is quite large, and requires a triple-gang electrical box. The 6287 can usually fit behind the switch in a deep electrical box or in the junction box for the first light in the string.
Jeff
Thanks a lot Jeff. I have two separate lines I'd need to filter. One runs to two fixtures, both with 4 32 watt bulbs each (256 total watts), and the other runs to 5 fixtures, all with 4 32 watt bulbs each (640 total watts). Did I see somewhere that I needed to figure amps by watts/120 volts? If that is the case, I believe I need the XPF because I'm over 5 amps on the 5 fixture line. And all I have to do is splice the filter into the line somewhere between the fixture(s) and the switch?