With the Vivoactive 3 do I have to use a Garmin Chest Strap or am I able to use other models of a Chest Strap to monitor my Heartrate? If I can use others what others can be used? Wahoo, Polar or what? Does a HRM Chest Strap have to be Ant+ or will the watch find it by way of it being Bluetooth. I have tried 2 Chest Straps a Wahoo would connect but not stay connected and an old Polar that the watch wouldn't even find.