Old t5 light diffuser plastic, useful?

I have some of that rough feeling, clear plastic light diffuser stuff from a t5 light fixture. Does anyone know if it's at all efficient to diffuse your light with this stuff, or am I about to turn my cobs into incandescents by doing this?

Thanks!

Major photon blockage, I would imagine.

I removed the cover from my T12 shop light, I read that it may contribute to blocking certain light, like uvb? And with T12's being weak I want all the usable light getting to the plants.

I would avoid using a diffuser, it's going to block some useful light. I don't even like air cooled hoods as the glass blocks some light.