diff --git a/garage/templates/garage.configmap.yaml b/garage/templates/garage.configmap.yaml
index 4a60a95..5f60c28 100644
--- a/garage/templates/garage.configmap.yaml
+++ b/garage/templates/garage.configmap.yaml
@@ -92,7 +92,16 @@ data:
     metadata_auto_snapshot_interval = "{{ $settings.metadataAutoSnapshotInterval }}"
 
     block_size = "{{ $settings.blockSize }}"
+    # An integer is the zstd level; the literal "none" disables compression and
+    # has to be QUOTED to stay valid TOML. Garage's deserializer takes exactly
+    # those two forms - and 0 is not the second one: it is a valid integer that
+    # zstd reads as its default level (3), so writing 0 to "switch compression
+    # off" quietly turns it up.
+    {{- if kindIs "string" $settings.compressionLevel }}
+    compression_level = {{ $settings.compressionLevel | quote }}
+    {{- else }}
     compression_level = {{ $settings.compressionLevel | int64 }}
+    {{- end }}
 
     # Inter-node RPC. There are no other nodes here (no bootstrap_peers, no
     # kubernetes_discovery - see values.yaml), but Garage binds this listener
diff --git a/garage/values.schema.json b/garage/values.schema.json
index c5ca314..b33211e 100644
--- a/garage/values.schema.json
+++ b/garage/values.schema.json
@@ -77,9 +77,11 @@
           "minLength": 1
         },
         "compressionLevel": {
-          "description": "zstd level for stored blocks; 0 disables compression.",
-          "type": "integer",
-          "minimum": 0
+          "description": "zstd level for stored blocks, or the literal string \"none\" to disable compression. NOT 0 for disabling: Garage accepts 0 as an integer and zstd reads it as its default level (3), i.e. more compression than 1, not none. Negative integers are zstd's fast modes.",
+          "oneOf": [
+            { "type": "integer" },
+            { "type": "string", "enum": ["none"] }
+          ]
         },
         "bindAddress": {
           "description": "Host part of the S3, web and RPC listeners. '[::]' accepts IPv4 as well while net.ipv6.bindv6only is 0.",
diff --git a/garage/values.yaml b/garage/values.yaml
index e54d38a..85f1601 100644
--- a/garage/values.yaml
+++ b/garage/values.yaml
@@ -212,7 +212,15 @@ garage:
   # Garage's defaults, exposed because they are the two knobs that trade disk
   # against CPU. blockSize is the chunk size objects are split into;
   # compressionLevel is the zstd level for stored blocks (1 = fast, higher =
-  # smaller, "none" is not a value here - set 0 to disable).
+  # smaller, negative levels are zstd's "fast" modes).
+  #
+  # TO DISABLE COMPRESSION, WRITE THE STRING "none" - and not 0, which is the
+  # trap this comment exists for: Garage's deserializer accepts an integer or
+  # the literal "none" (src/util/config.rs, deserialize_compression), and 0 is
+  # a perfectly valid integer that zstd reads as "use my default level", i.e.
+  # level 3 - MORE compression than the 1 below, not less. The schema therefore
+  # accepts an integer or exactly "none", and the ConfigMap quotes the string
+  # form so the rendered TOML stays valid.
   blockSize: "1M"
   compressionLevel: 1