I have access to both a heated outdoor Olympic 50-meter pool and indoor 25-meter pool at Fort Sam Houston (San Antonio, Texas) and swim 1000 meters daily for fitness. I wore a Fenix 3 HR for the past 5 years and just bought a Fenix 7X Sapphire last week. I gave up on using the Fenix 3 HR for the pool swim application and instead just used the stopwatch to record my time on each lap because I could never get it to count pool lengths correctly. This week I have had the same problem with the new 7X Sapphire Solar. For example, today I swam 1000 meters (10 laps in the 100-meter pool) and used the pool swim app. I set the pool length to 50 meters and auto rest set to off. I rest for 20 seconds after each 100-meter lap and hit the lap button upon stopping and again on starting back swimming. The intervals record correctly. The pool length numbers are way off. By a factor of 2x. This makes distance recordings and all averages on the date nonsensical.
I have a good crawl stroke but do not do flip turns. I do touch hard and push off and glide, but do no flip turns. After the 100-meter lap it almost always records 200 meters and 4 lengths vs the correct 2 pool lengths. It recorded 200 meters on 8 of the 100-meter laps. On two laps it recorded 150 meters. On the ten laps, it never got it right. The pool length number should be 2, not 3 or 4.
I went into Garmin Connect and edited the final reported distance of 1700 meters to 1000 meters. That gave me ten good intervals (laps) with the correct time. But Garmin Connect would not let me edit the number of lengths of each interval from 4 to the correct 2 - only the total distance of the swim. That made the data on each interval (lap) meaningless.
If I can't get this situation resolved, I will again give up on the pool swim app on the Fenix 7X Sapphire like I did on the Fenix 3 HR.
I know this is a problem with other users, but I wanted to fully explain my situation because I know how to use this watch.
If you have to do a flip turn to make this work, please Garmin ... say so.