I'm also back from a couple year break and having a great time! :)
First chamber I did 1 block of the foam that comes with tank. I threw out the sock I don't trust that there's no bypass if it gets plugged and I know I wouldnt change or clean it as much as it needs to be lol
Second chamber is the bag of charcoal and the bio balls which I emptied half way out. The bags are huge. I might take out the bio balls at some point after the new rock is in there for a few months.
Also in the second chamber is the skimmer and my heater, I also moved my GHL temp and PH probes in there. In preparation for an auto top off in the third chamber.
Third chamber I cut the second block of foam and put it under the pump to remove the hum it was making.
Keep us updated as you get stuff added in there cant wait to see the grow out