Dumbest Question Ever About Under Gravel Filter

[MermaidMel]

I bought a small round ugf for my betta's 3 gallon bowl
It was basic, had very little instructions other than where to put the tubing to the air pump
It doesn't have 2 tubes coming out of it like the other's I've seen, just the one tube that has a little carbon/media compartment on top
QUESTION: Does the compartment have to be totally submerged under the water or sticking out a bit, or totally sticking out?

 

[arvlyn]

I bought a small round ugf for my betta's 3 gallon bowl
It was basic, had very little instructions other than where to put the tubing to the air pump
It doesn't have 2 tubes coming out of it like the other's I've seen, just the one tube that has a little carbon/media compartment on top
QUESTION: Does the compartment have to be totally submerged under the water or sticking out a bit, or totally sticking out?

I've only seen and used them totally submerged. It'll aerate the water that way also.