diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 59c2b20de..ada5ab060 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -2061,7 +2061,7 @@ void PrintConfigDef::init_fff_params()
     def->ratio_over = "perimeter_extrusion_width";
     def->min = 0;
     def->mode = comExpert;
-    def->set_default_value(new ConfigOptionFloatOrPercent(100, true));
+    def->set_default_value(new ConfigOptionFloatOrPercent(200, true));
 
     def = this->add("min_print_speed", coFloats);
     def->label = L("Min print speed");
@@ -3530,7 +3530,9 @@ void PrintConfigDef::init_fff_params()
     def = this->add("z_step", coFloat);
     def->label = L("Z full step");
     def->tooltip = L("Set this to the height moved when your Z motor (or equivalent) turns one step."
-                    "If your motor needs 200 steps to move your head/plater by 1mm, this field have to be 1/200 = 0.005");
+                    "If your motor needs 200 steps to move your head/plater by 1mm, this field have to be 1/200 = 0.005."
+                    "\nThe gcode can't write a value below 0.001 so any value below or equal that is equivalent to disabling the feature."
+                    "\n0 to disable.");
     def->cli = "z-step=f";
     def->sidetext = L("mm");
     def->min = 0.0001;
diff --git a/src/libslic3r/Slicing.cpp b/src/libslic3r/Slicing.cpp
index 06080116c..f71ea23c1 100644
--- a/src/libslic3r/Slicing.cpp
+++ b/src/libslic3r/Slicing.cpp
@@ -25,12 +25,14 @@ static const coordf_t MIN_LAYER_HEIGHT = 0.01;
 static const coordf_t MIN_LAYER_HEIGHT_DEFAULT = 0.07;
 
 inline coordf_t check_z_step(coordf_t val, coordf_t z_step) {
+    if (z_step <= EPSILON) return val;
     uint64_t valint = uint64_t(val * 100000. + 0.1);
     uint64_t stepint = uint64_t(z_step * 100000. + 0.1);
     return (((valint + (stepint/2)) / stepint) * stepint) / 100000.;
     //return int((val + z_step * 0.5) / z_step) * z_step;
 }
 inline bool test_z_step(coordf_t val, coordf_t z_step) {
+    if (z_step <= EPSILON) return val;
     uint64_t valint = uint64_t(val * 100000. + 0.1);
     uint64_t stepint = uint64_t(z_step * 100000. + 0.1);
     return valint % stepint == 0;
diff --git a/src/slic3r/GUI/Tab.cpp b/src/slic3r/GUI/Tab.cpp
index e0c77fd02..8800b98d4 100644
--- a/src/slic3r/GUI/Tab.cpp
+++ b/src/slic3r/GUI/Tab.cpp
@@ -45,7 +45,10 @@ namespace GUI {
 wxDEFINE_EVENT(EVT_TAB_VALUE_CHANGED, wxCommandEvent);
 wxDEFINE_EVENT(EVT_TAB_PRESETS_CHANGED, SimpleEvent);
 
+//same as the slicing.cpp method, but it's easier to redefine it here
+// maybe i should have written it in the header.
 inline coordf_t check_z_step_temp(coordf_t val, coordf_t z_step) {
+    if (z_step <= EPSILON) return val;
     uint64_t valint = uint64_t(val * 100000. + 0.1);
     uint64_t stepint = uint64_t(z_step * 100000. + 0.1);
     return (((valint + (stepint / 2)) / stepint) * stepint) / 100000.;