FT8 and ALC on 6500

you can lower the audio output on WSJT program itself, look for the sliding bar
on the right to lower the TX power by 2 or 4 dB, you will see your ALC audio level go down on the
flex panel.

You can also click on the DAX icon on  your taskbar and lower the TX Audio level directly
there.

Adjust so that the peak audio level is a bit below the red zone on the Flex audio level indication panel 

On your level meter you need to stay below 0 DB, as long as the level indicator is yellow and not RED you are putting out a clean signal. The Way I do it is, I leave the Pwr setting on the right side of the main WSJT-X screen up all the way and adjust my audio level in the DAX TX STREAM adjustment in the DAX Control panel, I find once I set this it is good for all bands and power levels and never need to mess with it again but always keep an eye on it to make sure. Power can then be controlled by the SSDR RF Power slider. When others tell you its an ALC issue, they are correct on a  conventional radio where digital audio levels should be set up right before you see any deflection reading on the radios ALC Meter.

Others may do it differently but this works perfect for me.

very nice way to show it, it works perfect for me -5.1 db