diff --git a/client/public/version.js b/client/public/version.js
index 6bb8d72..54feca3 100644
--- a/client/public/version.js
+++ b/client/public/version.js
@@ -1,5 +1,5 @@
 // Maintainer-controlled web client version.
 // Format: YYYY.MM.DD Rn (example: 2026.02.20 R2)
-window.CHGRID_WEB_VERSION = "2026.02.21 R86";
+window.CHGRID_WEB_VERSION = "2026.02.21 R87";
 // Optional display timezone for timestamps. Falls back to America/Detroit if unset/invalid.
 window.CHGRID_TIME_ZONE = "America/Detroit";
diff --git a/client/src/audio/effects.ts b/client/src/audio/effects.ts
index 6e409f6..d85f02f 100644
--- a/client/src/audio/effects.ts
+++ b/client/src/audio/effects.ts
@@ -21,7 +21,7 @@ export type EffectRuntime = {
 
 export function clampEffectLevel(value: number): number {
   const clamped = Math.max(0, Math.min(100, value));
-  return Math.round(clamped / 5) * 5;
+  return Math.round(clamped * 10) / 10;
 }
 
 export function disconnectEffectRuntime(runtime: EffectRuntime | null): void {
diff --git a/client/src/main.ts b/client/src/main.ts
index c5b88f0..60680c1 100644
--- a/client/src/main.ts
+++ b/client/src/main.ts
@@ -1831,8 +1831,8 @@ function handleItemPropertyEditModeInput(code: string, key: string): void {
       signaling.send({ type: 'item_update', itemId, params: { effect: normalized } });
     } else if (propertyKey === 'effectValue') {
       const parsed = Number(value);
-      if (!Number.isInteger(parsed) || parsed < 0 || parsed > 100) {
-        updateStatus('effectValue must be an integer between 0 and 100.');
+      if (!Number.isFinite(parsed) || parsed < 0 || parsed > 100) {
+        updateStatus('effectValue must be a number between 0 and 100.');
         audio.sfxUiCancel();
         return;
       }
diff --git a/server/app/server.py b/server/app/server.py
index 0cdaef2..154f381 100644
--- a/server/app/server.py
+++ b/server/app/server.py
@@ -654,7 +654,7 @@ class SignalingServer:
                     next_params["channel"] = channel
 
                     try:
-                        effect_value = int(next_params.get("effectValue", 50))
+                        effect_value = float(next_params.get("effectValue", 50))
                     except (TypeError, ValueError):
                         await self._send_item_result(client, False, "update", "effectValue must be a number.", item.id)
                         return
@@ -663,7 +663,7 @@ class SignalingServer:
                             client, False, "update", "effectValue must be between 0 and 100.", item.id
                         )
                         return
-                    next_params["effectValue"] = round(effect_value / 5) * 5
+                    next_params["effectValue"] = round(effect_value, 1)
                 item.params = next_params
             item.updatedAt = self.item_service.now_ms()
             item.version += 1