Don't mean to beat a dead horse about this...
It's about that small slit below the middle of the black plastic separator.
I've had my fluval spec V for about 2 weeks now and the first thing I did after perusing reviews/mods was to plug that slit with silicon. So I did, and I really can't say that inflow is improved. It makes sense, that water would therefore flow in from the top vented section and then down, but water is pretty stagnant up in that section.
One more thing..
The pump placement. Per the instruction manual, it says to position the pump so that the intake is against the black plastic. Originally I had it rotated clockwise 90 degrees (looking from the top) because it made sense to me to have the pump intake closest to the sponge and not pushed up against a wall basically. In the end, I changed it back to what the instruction manual said because I thought Fluval did their research and should know best.
So just curious, how's your guys' placement of the pump? Did you follow the instructions or turn it? Also thoughts on siliconing/covering up the small slit halfway down? Help with flow or not?
Hopefully we can all help make this tank the most efficient it can be!