Improved insulation!
I have a follow-up on my own last post "The Ice Probe chiller works! Sort of..." If you studied the numbers carefully, you probably felt like I did that the Ice Probe should have greater cooling effect on a two-gallon set-up. The problem with pickle jars is that they are very thin. I cannot figure out how to measure one without breaking it, but the walls appear to be less than 1/8" thick. This allows heat to leak in fairly quickly. However, on a hot day I would be willing to insulate the back half of each jar; and in a pinch, I could even go for full insulation.
So I made an insulating layer to cover half a jar using damp paper towels, spray starch, and a little white glue to finish when dry. With both semi-circular insulators in place, I got an extra 4 degrees pull-down. So the total is: 3 degrees with evaporation + 5 degrees with two Ice Probes + 4 degrees with improved insulation = 12 degrees. This is enough for most hot summer days!
No doubt your tank is bigger and thicker than mine. But the trick of using styrofoam or paper towel layers can be easily applied to a tank of any size. Beyond a certain thickness, extra layers of insulation make little difference. I am still not using the controller unit to regulate the temperature.
I am still waiting for someone to recommend a low-wattage low-flow rate commercial chiller that costs less than $300. Has anybody seen or tried one?
-Boondocks | 
