diff --git a/.changeset/thirty-phones-leave.md b/.changeset/thirty-phones-leave.md
new file mode 100644
index 0000000..77de68c
--- /dev/null
+++ b/.changeset/thirty-phones-leave.md
@@ -0,0 +1,5 @@
+---
+"@effect-rx/rx": patch
+---
+
+disable TTL if idleTTL is set to 0
diff --git a/packages/rx/src/internal/registry.ts b/packages/rx/src/internal/registry.ts
index a33e405..f1e21db 100644
--- a/packages/rx/src/internal/registry.ts
+++ b/packages/rx/src/internal/registry.ts
@@ -94,12 +94,16 @@ class RegistryImpl implements Registry.Registry {
     return this.subscribe(rx, constListener, constImmediate)
   }
 
+  rxHasTTL(rx: Rx.Rx<any>): boolean {
+    return !rx.keepAlive && rx.idleTTL !== 0 && (rx.idleTTL !== undefined || this.defaultIdleTTL !== undefined)
+  }
+
   ensureNode<A>(rx: Rx.Rx<A>): Node<A> {
     let node = this.nodes.get(rx)
     if (node === undefined) {
       node = this.createNode(rx)
       this.nodes.set(rx, node)
-    } else if (!rx.keepAlive && (rx.idleTTL || this.defaultIdleTTL)) {
+    } else if (this.rxHasTTL(rx)) {
       this.removeNodeTimeout(node)
     }
     return node
@@ -138,7 +142,7 @@ class RegistryImpl implements Registry.Registry {
   }
 
   removeNode(node: Node<any>): void {
-    if (!node.rx.keepAlive && (node.rx.idleTTL || this.defaultIdleTTL)) {
+    if (this.rxHasTTL(node.rx)) {
       this.setNodeTimeout(node)
     } else {
       this.nodes.delete(node.rx)
diff --git a/packages/rx/src/internal/runtime.ts b/packages/rx/src/internal/runtime.ts
index 88c4433..1095e76 100644
--- a/packages/rx/src/internal/runtime.ts
+++ b/packages/rx/src/internal/runtime.ts
@@ -4,6 +4,7 @@
 import { NoSuchElementException } from "effect/Cause"
 import type * as Effect from "effect/Effect"
 import * as Exit from "effect/Exit"
+import * as FiberId from "effect/FiberId"
 import * as Runtime from "effect/Runtime"
 import { SyncScheduler } from "effect/Scheduler"
 
@@ -50,6 +51,6 @@ export const runCallbackSync =
     fiberRuntime.addObserver(onExit)
     return function() {
       fiberRuntime.removeObserver(onExit)
-      fiberRuntime.unsafeInterruptAsFork(fiberRuntime.id())
+      fiberRuntime.unsafeInterruptAsFork(FiberId.none)
     }
   }