Looking back at your op pic it looks like you have a mini fridge element in there. Is that correct? Are you running that to keep temps down? I had the same set up for a few years and the only issue I had, which you may find to, was during hot humid periods if I was running the fridge a lot I'd get ice build up on the coil/fins and it would end up losing the ability to cool so much so that it would continuously run and provide no cold output (basically the cold stayed inside the brick of ice around the fins). I fixed the issue with a small fan blowing on the chiller element/fridge fins (the part that gets cold) which keeps the condensation from settling there. With that set up I was able to lager in the chamber with temps in the 70s outside. Though my chamber was a bit smaller than yours appears. Either way it definitely improved my beer a lot.