I'm rather new to this hobby, and to be honest, I don't have the slightest idea what I'm looking at. I understand intake/outake, but that's... So much. =O
Let me help you out. There are three different filtration categories on this tank.
1)The primary filter are the two green canisters you see in the stand. They are connected together with the big one pushing water through the small one and back into the tank. Intake is behind the sponge on the right. Outflow is a glass lily on the upper left hand corner.
2)There is also an air pump driving the Undergravel Filter (UGF) and the sponge Filter. The black tube on the left with the bubbles coming out and the black sponge on the right is what you're looking for.
3)The breeder box has it's own ZooMed 501 filter that draws water from the main tank and puts clean water into the breeder box. The box overflows back into the main tank. That's the little tiny canister by the electrical outlet picture. The ZooMed 501 is not by the electrical outlet anymore....was just there for testing purposes.
There are also some extra tubes at the moment, because I'm running CO2 to kick start the plants. The CO2 will be removed later. You can also see the paintball CO2 next to the two green Eheim filters.
That's pretty much it.