Still contemplating drilling a hole in the lid to put the hose through to minimise heat loss.
Hi!
That's something that I've also considered. I've even thought about fitting the lid with a male quick disconnect with a hose barb, but that's possibly overthinking the problem.
In case you haven't investigated yet, there's an outer and inner lid but there's no insulation in the void. It was easy to take apart and a bit of a bu**er to put back together. I had thought about putting some insulation material in the void, but that could be overegging the pudding, especially reading @donchiquon's post.
One further point about the system overall. I've tried it with the hoses pushed onto the hose barbs and was getting tiny bubbles recirculating. Since I added jubilee clips to each hose barb the bubbles are gone.