Just to make sure I'm seeing it right - there is no water (other than melted ice) in the second chamber, right? That seems like too much work to me, but since you've come that far, I've got a suggestion to get you even more cooling. Take some tubing from your hose port to the smoke chamber, but coil it up in ice water. That way the draw has to go through the tubing and spends more time chilling.
I've been meaning to mess with rock salt and ice in the base. The salt depresses the freezing point of water, which means your water can get much colder. One of these days I just need to remember to pick up a bag of salt