hi has anyone had the experience of cannulas sealing themselves off or the body doing it? Since Thursday last week I have had my cannulas sealing off after a couple of hours. I am on the new Medtronic 640g with silhouette soft cannulas or I have also been trying the Minimed Mio 30 (these are the ones that have been sealing off) I have been inserting at the correct angle (with the delivery system of the Minimed) but less than three hours later its sealed off. I have used 7 over the course of the weekend and ended up with an average of 27 mmol and used nearly 400ius of insulin to try and get myself back on an even keel. I have went back to the silhouette soft cannula and have not sealed off (yet). I am calling Medtronic later today to report it, I was wondering if any other pump users had experienced this as well. I am understandably a bit tired and grumpy after a weekend of fighting high sugars that wasn't my own doing. Any advise greatly received. Take care everyone.