MY FILTER AND GLASS TOP

I have a power filter on the back of my 20 gallon tank...my glass top does not close all the way because of the filter...so it is pretty much open air...is this ok? I know my water evaporates quicker but is there anything I need to do?

you have the power filter,so it produces much oxygen..so no need to open the glass top of your tank..so if you close this it will be better...

Some of the glass tops have a plastic strip on back so you can make room for external filters. Some other glass tops are in two pieces, and you could probably replace one of the glass pieces with Plexiglas (acrylic), which can then be cut out to accommodate the filter. The Plexiglas, however, will warp.

One more idea: remove one chunk of glass and lop off enough to accommodate the filter. Then get a thin sheet of acrylic, cut it to the profile of the filter, and tape it to the glass.

Actually there is only about an inch opening across the top...the glass goes across and the light fixture sits on top of that and also to prevent any fish from jumping out...

Can you scoot the glass forward enough to accommodate the filter? If so, you could fill in the gap with acrylic.