you will not find this at a hardware store. Nothing food safe rated for the temps needed.
You'll want this Thermoplastic Rubber Tubing
2nd thing down the page.
Actually the first one listed will work to for transferring to a BK but isn't available in 1/2".
You can still brew tonight though. Just drain into a bucket from the nipple on your ball valve and transfer to the BK.
This stuff can definitely be used with your pumps too.