Tank valve pressure relief Question

I've got an Omega 75 tank purchased from AOA ( apexs )and it's fine accept for one issue. The button that you must push to bleed off the pressure after the fill is extremely difficult for me to push. Don't know if it's my old weak fingers or a problem with the valve or it it's just the nature of the equipment. 

I'd like to replace the valve or modify the valve if possible with something more user friendly if there is such a item. .

And while I'm asking questions if I'd get another tank valve are they just screwed into the carbon fiber tanks. What's involved with that.

Mod edit: moved to compressor section