Just used my watch for the first time today for a swim. I'd read that I didn't have to do anything and it would track the swim automatically if I swam for more than 10 mins. I swam for 30 mins continuously (apart from turning round) in a relatively empty pool and the watch hasn't tracked any activity. Anyone else have the same problem? Do I have a faulty watch or is it just best to select swim manually before hand? Thanks.