Listening in the dark-Fluorescent lights causing hum

Recently my fluorescent lights have begun causing a hum in my stereo. This wasn’t noticeable before. Turn off the overhead lights and the hum disappears. How can I treat this? I have too many fluorescent light fixtures to replace all of them. I tried plugging the equipment into a Furman DST-8. No improvement. I’ve heard ground loop isolators work but can effect sound quality. Would it be worth buying one to try? Is that effective in this case? I don’t mind listening with the fluorescent lights off, but I can’t always do that. You help is appreciated. 
I'd bite the bullet and replace those lights:  you'll have to eventually, no?, or deal with that black presumably carcinogenic crap that leaks out of all the ballasts as they wear out.
I tried plugging the equipment into a Furman DST-8. No improvement.

Right. Only one thing will work: ditch the lights. The ballast tends to go bad over time and once this happens there really is nothing to do but replace. You can try LEDs and maybe luck out. But usually it is the ballast and game over.
So, are you having actual hum from the speakers, or is it mechanical hum from a transformer??
erik_squires -Actual hum from the speakers. Is there a way to figure out which fixture? There are 9. 
It’s Possible that it is the same circuit. I’ll check later tonight. I’m not sure I could move them without a new breaker box. The current one is maxed. Of course the easy solution doesn’t work for me. I’m never that lucky. 
Pop in led tubes. Less power usage and less noise. More lumens.
With sleepy Joe in charge you will probably have to anyway.
Replace the lights, and it is highly unlikely there is anything carcinogenic in your ballasts. That was the 60's.
Yup.  That was the vintage of mine. All gone now--tubes, horrible light, always hummed, often didn't turn on, and dripped from the ballast.  I'm glad they've improved, but I doubt I'll ever try them again.