Installing MH lighting...what do you cover yours with?

[pisces01]

We will be installing MH lighting in our custom made canopy this weekend and we need to know which type of covering to use.
By covering I mean, what do you have between your lights and the tank water?
Will glass block out some needed wavelengths?
Any suggestions...?
Thanks,
Alyse

 

[mr . salty]

I have nothing but about four inches of AIR between my bulbs and the water.

 

[7up]

I have a sheet of plexi-glass between my MH's and the water. It helps reduce the heat transfer to the water and last year I had an old bulb break. I'm glad I had the plexi. However, If you can go without.... probably the best for light quality.

 

[pisces01]

Thank you for your responses. Does anyone know exactly what your are losing from your light quality by having a protective cover?