glass over the tank?

[MNFishGuy]

I am setting up a reef tank, and I have a four bulb HO fixture that sits about four inches about the top of the tank. The bulbs are protected by a cover built into the fixture, but I was wondering if I should place glass on top of the tank anyway to reduce evaporation, splashing, etc.

Thank you!

[Parrothead]

I wouldn't, you really want the top to be open to aid in the oxygen exchange

[Bloodydecks]

Parrothead, I won't say your wrong, as i have never tested the O2 levels with my lids on then off.....but if he has a overflow box with with a sump that has a trickle tray, or a skimmer, or really good surface agitation, or really good water flow into the sump, IMO and in my experience the lids on or off wont make a bit of difference.

Assuming your not keeping corals that need really intense light, I would put the glass lids on the tank. Mainly to slow the evaporation. Just keep the lids clean as possible, as the glass will filter out some of the light, even if its spotless, which it never will be after a week or two.