MH Aqualight question

[DCFix]

Can someone explain to me why I have to use the
Coralife Aqualife with a glass canopy?

I was hoping to put this over my plexi. Is it a heat problem that I could solve by using fans?

 

[Ti]

it's a PC fixture.
You won't need a fan

 

[ReefLife1680]

i see a PC fixture too? no need for fan or glass

 

[DCFix]

Thanks everyone for your help!