diff --git a/slsSupportLib/include/sls/ZmqSocket.h b/slsSupportLib/include/sls/ZmqSocket.h
index 4c8479441..75fa0fe2b 100644
--- a/slsSupportLib/include/sls/ZmqSocket.h
+++ b/slsSupportLib/include/sls/ZmqSocket.h
@@ -32,8 +32,9 @@ namespace sls {
 #define ROIVERBOSITY
 
 // high water mark for gui
-#define DEFFAULT_LOW_HWM           (25)
-#define DEFAULT_LOW_HWM_BUFFERSIZE (1024 * 1024) // 1MB
+#define DEFFAULT_LOW_ZMQ_HWM           (25)
+#define DEFAULT_LOW_ZMQ_HWM_BUFFERSIZE (1024 * 1024) // 1MB
+#define DEFAULT_ZMQ_BUFFERSIZE         (0)           // os default
 
 /** zmq header structure */
 struct zmqHeader {
@@ -113,14 +114,14 @@ class ZmqSocket {
     int GetSendHighWaterMark();
 
     /** Sets high water mark for outbound messages. Default 1000 (zmqlib). Also
-     * changes send buffer size depending on low hwm. Must rebind.  */
+     * changes send buffer size depending on hwm. Must rebind.  */
     void SetSendHighWaterMark(int limit);
 
     /** Returns high water mark for inbound messages */
     int GetReceiveHighWaterMark();
 
     /** Sets high water mark for inbound messages. Default 1000 (zmqlib). Also
-     * changes receiver buffer size depending on low hwm. Must reconnect */
+     * changes receiver buffer size depending on hwm. Must reconnect */
     void SetReceiveHighWaterMark(int limit);
 
     /** Gets kernel buffer for  outbound messages. Default 0 (os) */
diff --git a/slsSupportLib/src/ZmqSocket.cpp b/slsSupportLib/src/ZmqSocket.cpp
index 25b9f6e2e..c4c024179 100644
--- a/slsSupportLib/src/ZmqSocket.cpp
+++ b/slsSupportLib/src/ZmqSocket.cpp
@@ -106,9 +106,12 @@ void ZmqSocket::SetSendHighWaterMark(int limit) {
         throw ZmqSocketError("Could not set ZMQ_SNDHWM to " +
                              std::to_string(limit));
     }
-    if (limit < DEFFAULT_LOW_HWM) {
-        SetSendBuffer(DEFAULT_LOW_HWM_BUFFERSIZE);
+
+    int bufsize = DEFAULT_ZMQ_BUFFERSIZE;
+    if (limit < DEFFAULT_LOW_ZMQ_HWM) {
+        bufsize = DEFAULT_LOW_ZMQ_HWM_BUFFERSIZE;
     }
+    SetSendBuffer(bufsize);
 }
 
 int ZmqSocket::GetReceiveHighWaterMark() {
@@ -132,9 +135,11 @@ void ZmqSocket::SetReceiveHighWaterMark(int limit) {
         throw ZmqSocketError("Could not set ZMQ_RCVHWM to " +
                              std::to_string(limit));
     }
-    if (limit < DEFFAULT_LOW_HWM) {
-        SetReceiveBuffer(DEFAULT_LOW_HWM_BUFFERSIZE);
+    int bufsize = DEFAULT_ZMQ_BUFFERSIZE;
+    if (limit < DEFFAULT_LOW_ZMQ_HWM) {
+        bufsize = DEFAULT_LOW_ZMQ_HWM_BUFFERSIZE;
     }
+    SetReceiveBuffer(bufsize);
 }
 
 int ZmqSocket::GetSendBuffer() {