I recently bought a Forerunner 910xt for some triathlon training. I'm confused about its accuracy. It counts my laps perfectly in a 25 yard pool, but counts lots of extra laps in a 50 metre pool. My technique is the same, so I don't know why it would be so wildly different. On Monday this week, I swam 70 laps (1750 yards) indoors at the 25 yard pool, which was counted correctly. Today I swam 100 laps (2500 metres) at the 50 metre pool, and it counted 3900 metres: an extra 28 laps! What is it about the longer pool that would cause it to be so different?
