Sump Baffles
 

Quick question for the collective wisdom here. I'm converting a 40 breeder to a sump. How much smaller than the inside width of the tank is it recommended to have glass for baffles cut?

I have mine cut so there is a very small gap, just enough to easily twist the baffle into place. Usually say 3 or 4 mm less than the inside width or 3/16th or so inches. I like it so that with a bead of silicone all the way around, the baffle will be tight enough to stay in place without too much effort while its drying. The most I would do is have a 5 mm difference, but I prefer less myself.

Thanks. That's kind of what I figured; maybe about 1/8"; but wanted to get some second opinions.

for sure 1/8" to 3/16" is good