diff --git a/include/villas/hook.hpp b/include/villas/hook.hpp
index 27bd280c8..b43cfb27f 100644
--- a/include/villas/hook.hpp
+++ b/include/villas/hook.hpp
@@ -196,7 +196,7 @@ class MultiSignalHook : public Hook {
 
 protected:
 	std::list<unsigned> signalIndices;
-	std::list<std::string> signalNames;
+	std::vector<std::string> signalNames;
 
 public:
 	using Hook::Hook;
diff --git a/lib/hooks/rms.cpp b/lib/hooks/rms.cpp
index d2345a73d..449459cdc 100644
--- a/lib/hooks/rms.cpp
+++ b/lib/hooks/rms.cpp
@@ -68,7 +68,7 @@ public:
 
 			/* Add signals */
 			std::stringstream ss;
-			ss << "rms" << i;
+			ss << "rms_" << signalNames[i];
 			rmsVal = signal_create(ss.str().c_str(), "", SignalType::FLOAT);
 
 			if (!rmsVal)