What are your SOF temps?

I built a SOF style chamber with a modified cooling chamber design. I built two staggered shelves on one side and cut out the dead space on the other. I did this because I don't have the ability to freeze large bottles. Anyway, I can keep a 5 gallon carboy consistently at 50F (about 25 degrees below the room temp). I was wondering what the lowest temps are that others here are able to maintain and what modifications (if any) helped to get lower.

Sorry if this has been beaten to death. I didn't find much on a quick search.

I made one, but didn't use the inner wall or fan. I can get 2 primary buckets in there at the same time.

I placed 3 - 1 ga jugs and a 1/2 gal one in a few days ago. The temp on the therm strip inside went down to 52F. I've been recording the times and temps I checked so I'll have to get back to you with an update.

The ice was melted yesterday afternoon, but the temp was low so I'll have to change them out today.