Fitting Cork To Filled Tank

[gizmo001i]

Ok, this is probably a no no. But I have been looking at some of the tanks with cork bark backgrounds and have been thinking that it would look good in my tank. However, I don't really want to empty it as the plants are setup just right and I can't save very much of my water. Is it possible to fix cork to the back of the tank (inside) with it still fairly full of water, using the underwater fish safe glues on sale.
Also, if I do this, will I have problems with any water trapped between the cork and the glass going stagnant and bad. Any views and experience with this type of thing will be very welcome.
Many thanks
Ian

 

[smurfyy_2k3]

not really as cork floats and will soon come unstuck

 

[gizmo001i]

Either cork, or I have noticed that my local builders yard is selling slate tiles at 99p each.

 

[smurfyy_2k3]

i think slate is ok to go in the tank