You get what you pay for, u know?
Zoom stuff is way cheaper than other companies like Boss or Digitech, so .. you might wanna invest into something that's more reliable. Also, isn't the GFX-8 an old unit?
My
Some toughts about the Zoom products in this thread :
http://www.sevenstring.org/forum/gear-and-equipment/19841-compact-and-cheap-multi-fx-pedal.html
The Dark Wolf is pretty much the man regarding multi-fx units...