diff --git a/vu1_gui.py b/vu1_gui.py
index 3d09b48..623baff 100644
--- a/vu1_gui.py
+++ b/vu1_gui.py
@@ -456,6 +456,11 @@ body {
       Hüllkurve mit separatem Attack/Release + 2.-Ordnung Nadelmodell<br>
       Natürliches Einschwingen, weniger Zappeln, weicher Rücklauf.
     </div>
+    <div class="iec-box" id="natural-box" style="display:none">
+      <b>Natural+</b> — neue Ballistikformel<br>
+      Hüllkurve mit separatem Attack/Release + 2.-Ordnung Nadelmodell<br>
+      Natürliches Einschwingen, weniger Zappeln, weicher Rücklauf.
+    </div>
 
     <!-- Physics sliders -->
     <div id="physics-ctrls">
@@ -1076,6 +1081,9 @@ class PhysicsVU:
         # Natural+ Formel (neue Ballistik)
         self._natural_env = 0.0
 
+        # Natural+ Formel (neue Ballistik)
+        self._natural_env = 0.0
+
     # ── Biquad helpers ──
     def _calc_biquad(self, fc):
         w0 = 2.0 * math.pi * fc / self.sample_rate
@@ -1484,7 +1492,6 @@ def set_param(param, value):
         meter.mode = value
         if value == 'iec_true':
             meter._iec_z[:] = 0
-            meter._iec_fast = meter._latest_peak
         if value == 'natural_formula':
             meter._natural_env = meter.needle_pos
     elif param == 'monitor':
@@ -1519,7 +1526,7 @@ def reset():
         meter.needle_pos=0; meter.needle_vel=0; meter.peak_pos=0
         meter.mode='full'; meter.monitor=False; meter.bypass=False; meter.solo='off'
         meter.band_crossover=250; meter.band_lo_weight=0.6; meter.band_hi_weight=0.4
-        meter._iec_z[:]=0; meter._iec_level=0; meter._iec_fast=0; meter._natural_env=0
+        meter._iec_z[:]=0; meter._iec_level=0; meter._natural_env=0
     return jsonify({"ok": True})