Garmin HR monitor not being picked up

i am using the the wahoo kickr and have all my sensors paired but my garmin HR monitor is not.  is it not compatible?   

Are you on PC or Apple?

Are the Garmin monitor ANT+? If so do you have a ant+ dongle connected. 

i am on my iphone and yes it is ant+.  i will also use my imac starting in a few days.

i do not have a dongle connected.  do i need one? i thought garmin was auto recognized but i guess not since wahoo would want their own Hr recognized?

I assume everything is connected using Bluetooth and the Garmin is only ANT+ therefore it is not being picked up.