Originally Posted by
Markw
http:///forum/post/2531915
A sump is not a filter. A sump is a place to keep all of your equipment so that it does not have to be seen by onlookers. a sump wouldnt be viewable from the top of an aquarium beings its directly under it in most cases.
Um no a sump is a filter of sorts...... It just happens to be under your tank or in another room. Water from ur tank runs down into another tank where there can be tons of different things such as live rock, bio balls, live sand, algae, etc... Then the water is returned up to ur tank.... as for gas exchange in there, yes there is. Then a glass top wouldnt be a prob. Like i said earlier i have had a glass top for over a year on my nano and it has been fine. BUT thats only because i dont have a light on legs like the picture above.... Then i will either use nothing or egg crate. One of the draw backs to a glass top is that algae, and salt creep can form on the glass.