What are the temps while the growlights are on? That will help determine your future actions.
Keeping them between 75 and 85 is optimal, but can be fudged in either direction by a few degrees. Keeping them off of the bare concrete is important, tho. They prefer warm feet.

Is the insulation getting old and friable? (does it break-off from the insulation, and float around the room when the fans are on?) If so, you might want to remove it. If not, just keep the heat, fans and electronics away from it and you should be fine.

I've used spray paint to encapsulate (trap the fibers with paint) exposed fiberglass before, too. That might be an option that's acceptable to you. :jointsmile:
(I used to be an industrial hygienist, monitoring asbestos abatement workers...epoxy spray paints are one method of encapsulating small fibers...the other being spray glues...)