diff --git a/src/effect_matrix.cpp b/src/effect_matrix.cpp
index f12b158..e2ab435 100644
--- a/src/effect_matrix.cpp
+++ b/src/effect_matrix.cpp
@@ -144,13 +144,19 @@ MatrixEffect::MatrixEffect() {
 }
 
 RandomMatrixEffect::RandomMatrixEffect() {
-	_columns = new MatrixEffectColumn* [window->width];
-	for (int i=0; i<window->width; i++) _columns[i] = new RandomMatrixEffectColumn(window, random8(4), true);
+	// No need to initialize _columns, because that will have been done by ctor of MatrixEffect.
+	for (int i=0; i<window->width; i++) {
+		delete _columns[i];
+		_columns[i] = new RandomMatrixEffectColumn(window, random8(4), true);
+	}
 }
 
 RainbowMatrixEffect::RainbowMatrixEffect() {
-	_columns = new MatrixEffectColumn* [window->width];
-	for (int i=0; i<window->width; i++) _columns[i] = new RainbowMatrixEffectColumn(window, MatrixEffectColumn::DIR_SOUTH);
+	// No need to initialize _columns, because that will have been done by ctor of MatrixEffect.
+	for (int i=0; i<window->width; i++) {
+		delete columns[i];
+		_columns[i] = new RainbowMatrixEffectColumn(window, MatrixEffectColumn::DIR_SOUTH);
+	}
 }
 
 MatrixEffect::~MatrixEffect() {