OCLT good…but algae still in pool

I sleuthed last night. My skimmers have two fittings for pipes. One is connected, and the other is not. Its just a cavity. Well, one of them was FULL of crud.

The fountains are stone overflow bowls. Aside from scrubbing them, anything else I can do?

Do I have to scrub the Pump filter bucket cavities? The main filter housing?
 
Still stirring up crud. Lost fc overnight.

If both light boxes were loaded w algae, i have to assume that at least some of the conduit running to them is also? Is there any way to clean that?

Would a full pool drain help? Does algae die w/o water?
 
If both light boxes were loaded w algae, i have to assume that at least some of the conduit running to them is also? Is there any way to clean that?
Not typically. Algae needs light to live. Behind a light gets enough. Haven't seen a SLAM fail because of conduit.
Would a full pool drain help? Does algae die w/o water?
Full drain is not going to help.