didnt vote i use eggcrate

no glass but closed canopy (didn't want the light spilling out or glare)

It will depend on what fish you keep. If you keep wrasses or other known jumpers, you will at least want egg cr..

Hmm, my sump is bigger than my tank. And my skimmer injects air into the water. I think I'm ok :)
Seriously, I'd like to see an O2 content comparison between a tank with glass lids and without. I doubt you'd see a difference at all. As long as you have good flow, surface agitation and a sump that overflows from the main display, O2 would be my last concern. CO2 off gasses very readily, and temperature would play a bigger role in O2 content than glass lids.
The reason to not have glass is to maximize the light entering a reef tank.

I have an open top on mine, but have found my dogs running around with 4 different clownfish in their mouth from jumpers hitting the floor within the past 6 weeks. Thinking of going to closed top.

Both, open top on the reef and covered top on the FOWLR

Ok, then why do all the all in one tanks have covers and I haven't heard anything bad about these (re: being covered). I am new to reefing and am thinking about covering mine, so I am just wondering.

I had egg crate on top of my 20g and didn't like how the tank looked with it on under the metal halide, the tank is noticable brighter with it off and it didn't have a checker board reflection. A couple of months ago I put a glass lid that covers about 80% of the top just some room at the back for my HOB skimmer and filter. I have observed no difference in coral growth or colors and much less evaporation. I am also running T5HO's now to prevent over heating. I do have to clean the glass every week however to prevent build-up on the glass. So I think it is more of a maintenance issue and fish protection but a top could also trap heat if using MH IMO as evaporation is a major tank cooling factor.

awsome response! well i like the mesh idea.im gona do a half mesh at the back as my halides are bringing up the temp in the summer and they need the glass so they dont get splashed. ill have to do the same for my moms tank as she has temp problems in the summer and found out the hard way that jaw fish jump.kitty liked the fishy treat though.lol:twised:

Thanks for your input, glad to hear from someone who is doing it. I will be going the glass way. :biggrin: