The thing I didn't like about glass lids was it restricted my lighting and I had to make sure the salt "creep" or splash didn't coat the underside of the glass; you have to keep removing it and cleaning. Your temp is good, as far as oxygen do you have a pump breaking the water surface? If so, you should be good to go. the best test for checking oxygen levels is just watching the fish, if they are not breathing heavy, you should be ok. And as mentioned it will keep the carpet divers from doing a swan dive on your carpet. If you want the best of both worlds you can always remove the back half of the glass and replace it with egg crate