Originally Posted by andrewmchugh
7/16 Primochill with 1/2" barbs.
Random forum lurker chipping in two cents here. Doing 7/16 ID tube on 1/2 in barbs will give you a VERY tight seal, and a LOT of people swear by this. But if/when you try to remove the tube from the barb, it becomes a complete pain, and you'll most likely want to just cut the tubing off and replace that section. This is especially true for acetal blocks, as trying to wrench the tube off of the barb can strip the threads on the block itself (and acrylic can crack like this too). But once assembled, tubing is relatively cheap, and not something you pop off frequently, so this would be a minor thing down the road. Otherwise, if you go for 1/2 in ID tube on a 1/2 in barb, do yourself a favor and factor in some good quality clamps. Just something to keep in mind. Otherwise, looks like a good parts list to me, though you might consider adding a t-junction for a drain valve - makes maintenance time much less of a hassle.