Fitbit v Garmin for swimming/aqua exercise??

[Minitoots]

I was given a 'Garmin vivosmart HR+' for Xmas to use for swimmng/ aqua exercise. My partner checked lots of online reviews/ specs to see what would be best under ?100 and this says it is waterproof to 50m. Has anyone used this model to record swimming or aqua activities? I don't want to set it up until I'm sure it will work for this because the Garmin tech help person was quite vague- apparently it needs to be altered from 'walk/ run' to other, but then there are several posts on the Garmin forum to say even when you do that, it does not work for heart rate when in water. Other posts say it does not record distance when in water either although the tech help person at Garmin said it should do.... It cost about ?80 and I don't want to spend a lot more on a different one, as I can use health and exercise apps my phone to check most of the other things I need to track for walking and cycling.

If anyone uses a fitbit, garmin or other for aqua aerobics and swimming I'd be interested to hear from you thanks.