Reply To: DIY
Atlantis,
this won’t help much for an already-wet tank, but another thing you could do is to use some silicone to put in plastic “brackets” (think cheap — strips of your roofing material? a thin slice of a square milk jug?) at the front and back where you want the divider. Once the silicone dries and the tank is full, you can just slide the divider down into those guides when you want it in. The downside, of course, is that the position is sort of a permanent choice.
I think your plastic mesh idea is fantastic for allowing water to flow through, but not fishies. I once saw an idea on the web for using mesh like that to grow a “living wall” of java moss on the back of the tank. I’ll see if I can find the link.