Zwift wattage lower than Stages Power Meter

Not sure of this is a Zwift issue or a TACX Flux issue. When I first started doing Zwift rides with the Flux, the Power on Zwift was fairly close to the Stages Power Meter data readings. I guess it might not be a Zwift issue since it gets the Power information from the Flux?

Today, the Zwift Power was 20-30W lower than what the Stages PM on my Garmin was reading. I calibrated before the ride and then 30 minutes in. At one point in my 90 minute Free Ride, the wattage was stuck on 169W on Zwift for a bit, till I stopped and then started again. 

I guess I should try it for a few more days and see if this is an ongoing issue, 

 

I should probably also have TACX Utility going so I can see if the Power is similar to Zwift readings or the Stages. 

Sounds like you’ve already figured this out, but yes, Zwift only reads power from the devices you pair; so if you’re seeing differences between your Flux and your Stages, that’s purely a power measurement difference between the two of them.