Need help with Water Fitness/Aerobics

Since hurting my Achilles tendon, I've been water running, often holding light water weights or a belt.  The problem is that the HR is terrible.  I sort of need to see my heart rate live to see what zone I'm in, ETC.  I don't know if Garmin uses a different power profile for the HR sensor when using pool swim, or how to duplicate that for Water Fitness.  There is no Water Fitness activity available on Garmin so I just used Cardio.

Any tips would be appreciated.  I'm thinking of using my scoche HR band right next to my watch.  I know bluetooth or ant+ can travel about an inch or two under water, so it might work?  I know my Form Swim goggles for lap swimming using the polar HR works with it being about an inch away.

Thanks