This will be my first year to turn my aeration back on after a winter. When or what temp should I fire the air back up?? Do I gradually start it again like I did when it was new? Or can I just turn it back on and let it rip?? I know it is a little early yet but I want to be prepared. Plus I want to pull up my diffusers and clean them before turning them back on.

Flame, it sounds like good things are going on for you and your pond. I would take my time when turning the diffusers on. Why take any risk of killing your fish. That is what I did last year and it worked out well. No dead floating fish

As I have understood it, water temp is key. I usually restart mine when it reaches 50°F. And I don't go gradual, I just keep it on for the rest of the season. This is for Iowa/'up north'. If you can, monitor your water temps and that may influence when you restart.
Just my 2 cents. I'm sure one the limnologists can chime in.