Sound control on skype app

[Mooball]

Getting used to the difference between my mac version and the ipad version, but how can I turn down the vol of my caller? I have a mute button(ok) a video button (ok) but the button that looks like a sound button makes NO DIFFERENCE and seems permanently set at super loud. Have I missed something? Thanks

 

[sjleworthy]

Tried just turning down the main volume?

 

[Mooball]

Tried just turning down the main volume?

What main volume?
Each app has its own control as far as I can see

 

[MoonlitSonata]

What main volume?
Each app has its own control as far as I can see

volume rocker, right side of the ipad.