Tank Current

I finally transferred my black moor to his giant tank and at first he was swimming all over the tank all happy. Then when I went to feed him later, he is always in the same spot - the back left corner of the tank. I couldn’t figure out if he was just hiding back there (because he will swim out to the front to eat when I feed him). But then always ends up back in the corner. After my son put too much food in there this morning, I was prepping my siphon/bucket to clean it out and I noticed it all went to that back corner. I have 2 filters going and 2 air pump/aerators. What can I do to fix that to ensure he has free range and not getting caught in anything? I also have sand I will be adding today so I was planning on vacuuming this morning anyway! lol