Quick MH help

[GrimReapr1]

I just purchased some used MH's with ballast and socket. It's 2 MH 6,500k lights, 175 WATT a peice. Now my canopy is a small one, bit fitting the MH lights i still have room and all i need is a cover. The lights are a little old and i want HQI 10,000 k. So here comes the question. I want to buy a cover, glass seems to be my only option, but since I am using HQI, does it have to be UV protected glass?

The lights will be about 1-2" away from the glass, i know it's very close but i will be running some good ventilation and i have a chiller for the water. Any input on the cover would be very helpful.

Tank:
55 gallon Reef (48 x 13 x 21)
2 175 WATT, 6,500k MH
2 96 WATT PC
Auto top off

[Ninong]

Hi GrimReapr1, welcome to Reefland!

Regular tempered glass will work fine as a UV absorbing shield. My Aquastarlight fixture uses 3/16" tempered glass. Tempered glass is more heat resistant than regular glass.

[Holyreefer]

The problem with having a glass top is that the oxygen exchange will be lowered.

[GrimReapr1]

I never that about that, thanks for bringing that up. In my opinion that water falling down the overflow, the skimmer, and through the wet dry will be a significant enough to make sure there will still be a proper gas exchange... The glass cover will also have 2 small openings so i guess air can also go in. But again thank you for that point.