I only have 2 apple snails... which require feeding since they can't find anything. My hoplo cleans up any remains he finds. Top layer or bottom layer, doesn't matter for him. He looks like he enjoys searching for food too. He often squeezes through the smallest places (even that arch of the wood, or behind my filter or between the Java Fern leaves.Yeah, I don't mess with trying to get "the right kind of algae." Each of my tanks has a cleanup custodial crew meant to nip any algae outbreak in the bud.
Zach's 20 gal tank currently has the most light per gallon & the the only algae issue is green on some of the wood. His cleanup crew is a bit light at just (3) Otos and they're picky algae eaters. The other 20 gallon has a single Bristlenose Pleco and (7) Trilineatus Corys and they keep thiungs quite clean, at least until I get that new light fixture. The 36 gallon has a single female Bristlenose plus (2) Otos, and (2) huge Mystery Snails. Not a sign of algae in that tank whatsoever.
I just took a pic of him doing his headstands while he's digging in the sand. It's so funny when he does this, he's completely perpendicular to the sand and keeps munching on it.

The amount of dirt he kicked up after that... X_X