Your lighting schedule is fine and with proper nutrient levels shouldn't cause your algae breakout. I'd still reduce your lighting to 6-8 hours until you see the algae start to recede. Have them come on from 2pm-9pm instead of the morning. The ambient light from the room will be enough for your fish to "wake up" and swim around. I light mine from 10am to 8 pm
You don't list any fish in your "my info" so until we know their sizes it's hard to say if you are over feeding or not. You list 2 clowns, a 6 line wrasse, & a citron goby in
this post but we still don't know how big they are. I feed one cube to my 4 small fish every other day and cut the cube in half to feed in the morning and when I get home. My tang gets a 2"X3" clip of nori everyday though.
Fish always act like they are starving and will generally eat aggressively even if you just fed them 30 minutes ago. Overfeeding fish not only adds excess nutrients to your tank but also will shorten their life. A lot of us feed every other day but small multiple daily feedings are fine also IMO. I wouldn't feed a whole cube once a day personally since there is a greater chance for it to be wasted.
An overfed or starved fish isn't too hard to spot. Overfed fish usually have puffiness near the eyes and their stomaches are sticking out. Underfed fish have a more sunken in eyes and their stomaches are concaved slightly.
If your fish look "normal" then I'd reduce feedings slightly. My personal rule of thumb is that if the fish consume all the food in less then 30 seconds I'll give them slightly more. If it takes longer then 2 minutes then slightly less until all food is generally consumed within 1-2 minutes. I'd also reduce flake feedings as much as possible because they are usually more wasted and will drive your po4 up.
A clear reading on the po4 test usually means it's "testing" at 0 but that could mean your algae is just absorbing it.
As Devilishturtles mentioned a lot of newer tanks go through small algae breakouts even if you do use ro/di and sparsely feed. Reducing excess nutrients is the easiest way to "starve" the algae so it doesn't have anything to feed on.
The way you reduce your nutrients is by reducing feedings and frequently running your skimmer. How often do you run your skimmer? Are you getting good skimmate? (one cup a week or more)
Your clean up crew of 10 snails and 10 hermits is fine for now. Peppermint shrimp will often hide for days or even weeks if they molt. Even if one did die it shouldn't have any affect on your tank. If multiple snails die it can foul a tank though but if your nh3/no2/no3 are still 0 then it's unlikely.