Power Meter or trainer

Apologies if already asked. I’ve recently started to use a Tacx Flux with Zwift. What I’m wondering is, when pairing the power source, should I use my existing power meter or the trainer? If I use the PM does the trainer know what resistance to set for erg mode and does it still need to be calibrated??
Also, my HR monitor won’t pair with Zwift. I’d tried it with my Garmin and even the tacx app and both pick it up and I’ve done it separately with no other devices around.
Any advice appreciated.

Power meter will be more accurate than the trainer. It will also match what you use outdoors presumably.

You can select controllable as the trainer and power source as the power meter. Although some people say they get more of a lag and/or some erratic behaviour using this approach. I’m not sure if you need to calibrate it or not.

Some people with certain HR monitors have been having issues with pairing. Is it a Garmin dual band?

Hi Ben,

Thanks for the reply. If I’m using the power meter, I assume the app and trainer are still in sync for performance? For erg mode etc?

The HR monitor is an older garmin. Removal battery housing in the centre with a sensor either side.

Yes it should but some people have said they prefer it just through the trainer for erg mode. You’ll have to judge for yourself (different trainers and devices probably work less well than others).

Same HR monitor as me probably then. So it would only use ANT+. What computer/device are you trying to pair it to?

I use either an iPad or Samsung S8 phone.

IPad doesn’t have ant+ just Bluetooth so if it is the old Garmin HR then it will only do Ant+. It appears the S8 has ant+ so I would have expected it to work but according to the googles that is not the case (see section on Android) https://road.cc/content/feature/269529-how-set-zwift-try-indoor-training-any-device?amp

But then later I see this earlier post about android support

In mentions you should press the ANT symbol top left in the pairing screen. It might be worth having a little read there might be some other steps.