Hi, I am so lucky to own a pool with jetstream. Is there any wat that my Fenix 6X pro can measure swimming distance heen using the jetstream?

There is no way of measuring distance in this type of pool, and size is actually not the issue here. Counting distance in a swimming pool works on the principle that you change direction rapidly and make a short glide after each pool length.

I am not sure if thisis 100% correct. It applies for swimming in a pool, I agree.

I recently experienced a correct measuring in an outdoor swim of 1000m (500m each direction), but the GPS track itself was just showing 30m. The distance however was correctly showing up in Garmin Connect and Strava. During the activity I was wearing the 6X Pro on my left hand wrist, thus no continuous GPS signal available.

My guess is: Outdoor swimming is not only recorded via a GPS track, but also based on movement of the arms. Maybe it is worth giving it a try to set the activity type to swimming, not swimming pool, and see what happens.

SPIRITOFPHOTOGRAPHY said:

, but also based on movement of the arms.

Arm movement while swimming cannot be converted to distance in any reasonable way. An efficient swimmer will have a distance-per-stroke ratio several times higher than a poor swimmer. For open water swims GPS is used, and then special algorithms are applied to account for impaired GPS reception, with varying results. Obviously, this will not work when swimming stationary in a jetstream pool. The watch might show some distance covered but this is just due to GPS position being very noisy in a swimming scenario.

tmk2 said:

Arm movement while swimming cannot be converted to distance in any reasonable way. An efficient swimmer will have a distance-per-stroke ratio several times higher than a poor swimmer.

And yet- treadmill distance is estimated reasonably well- even though we all have different strides.  (although- it's probably based on the percentage of time your feet are on the ground- which is inversely proportional to speed across a wide range of runners)

There's an algorithm in open water swimming that uses accelerometers in conjunction with GPS to provide a reasaonable estimate of swimming distance and pace (cue the howls of protest from those who have issues with the OWS function). For this to work you need GPS path data. You will not get this data swimming in a flume even if outside.