50m lengths tracked as 25

[Lisa1985]

 

Today I swam 18 lengths in a 50m pool. And my Fitbit charge 5 logged 26 lengths in a 25m pool. How can it be so inaccurate?  Can I tell it before the length of the pool and will that help it’s accuracy?

it did the same last time I went but always before that it seemed accurate. 

any help appreciated. 

thanks

[Surfista]

You can set the length of the pool using the app.

As far as the lap count goes, I have an ongoing issue with getting an accurate count.

I know when my count is wrong because I always swim an even number of laps, but my count often comes up as an odd number.