diff --git a/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/BlockData.java b/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/BlockData.java
index 77aa20710..0e5516066 100644
--- a/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/BlockData.java
+++ b/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/BlockData.java
@@ -15,6 +15,7 @@
 import org.janelia.render.client.newsolver.blockfactories.BlockFactory;
 import org.janelia.render.client.newsolver.blocksolveparameters.BlockDataSolveParameters;
 import org.janelia.render.client.newsolver.solvers.Worker;
+import org.janelia.render.client.solver.SerializableValuePair;
 
 import net.imglib2.util.Pair;
 import net.imglib2.util.ValuePair;
@@ -59,7 +60,7 @@ public class BlockData<M, R, P extends BlockDataSolveParameters<M, R, P>> implem
 
 	// TODO: specifically collected should go into the Parameter objects? We need to make sure each has it's own instance then
 	// the errors per tile
-	final HashMap< String, List< Pair< String, Double > > > idToBlockErrorMap = new HashMap<>();
+	final HashMap< String, List< SerializableValuePair< String, Double > > > idToBlockErrorMap = new HashMap<>();
 	// coefficient-tile intensity average for global intensity-correction
 	final HashMap<String, ArrayList<Double>> idToAverages = new HashMap<>();
 	// TODO: goes into the ZBlockFactory??
@@ -109,7 +110,7 @@ public WeightFunction createWeightFunctions() {
 
 	public ResolvedTileSpecCollection rtsc() { return rtsc; }
 	public HashMap< String, R > idToNewModel() { return idToNewModel; }
-	public HashMap< String, List< Pair< String, Double > > > idToBlockErrorMap() { return idToBlockErrorMap; }
+	public HashMap< String, List<SerializableValuePair< String, Double >> > idToBlockErrorMap() { return idToBlockErrorMap; }
 	public HashMap<String, ArrayList<Double>> idToAverages() { return idToAverages; }
 
 	public HashMap< Integer, HashSet< String > > zToTileId() { return zToTileId; }
diff --git a/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/assembly/AssemblyMaps.java b/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/assembly/AssemblyMaps.java
index 8622d9ee3..636d5455a 100644
--- a/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/assembly/AssemblyMaps.java
+++ b/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/assembly/AssemblyMaps.java
@@ -9,15 +9,14 @@
 import org.janelia.alignment.spec.ResolvedTileSpecCollection;
 import org.janelia.alignment.spec.TileSpec;
 import org.janelia.alignment.spec.TransformSpec;
-
-import net.imglib2.util.Pair;
+import org.janelia.render.client.solver.SerializableValuePair;
 
 public class AssemblyMaps< M >
 {
 	final public HashMap< String, M > idToFinalModelGlobal = new HashMap<>();
 	final public HashMap< String, TileSpec > idToTileSpecGlobal = new HashMap<>();
 	final public HashMap< Integer, HashSet<String> > zToTileIdGlobal = new HashMap<>();
-	final public HashMap< String, List< Pair< String, Double > > > idToErrorMapGlobal = new HashMap<>();
+	final public HashMap< String, List<SerializableValuePair< String, Double >> > idToErrorMapGlobal = new HashMap<>();
 	final public Set<TransformSpec> sharedTransformSpecs = new HashSet<>();
 
 	/**
diff --git a/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/solvers/intensity/AffineIntensityCorrectionBlockWorker.java b/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/solvers/intensity/AffineIntensityCorrectionBlockWorker.java
index 56742b8d3..88f9474f7 100644
--- a/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/solvers/intensity/AffineIntensityCorrectionBlockWorker.java
+++ b/render-ws-java-client/src/main/java/org/janelia/render/client/newsolver/solvers/intensity/AffineIntensityCorrectionBlockWorker.java
@@ -33,6 +33,7 @@
 import org.janelia.render.client.newsolver.BlockData;
 import org.janelia.render.client.newsolver.blocksolveparameters.FIBSEMIntensityCorrectionParameters;
 import org.janelia.render.client.newsolver.solvers.Worker;
+import org.janelia.render.client.solver.SerializableValuePair;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -234,8 +235,8 @@ private void solveForGlobalCoefficients(final HashMap<String, ArrayList<Tile<? e
 				t.updateCost();
 				return t.getDistance();
 			}).average().orElse(Double.MAX_VALUE);
-			final List<Pair<String, Double>> errorList = new ArrayList<>();
-			errorList.add(new ValuePair<>(tileId, error));
+			final List<SerializableValuePair<String, Double>> errorList = new ArrayList<>();
+			errorList.add(new SerializableValuePair<>(tileId, error));
 			blockData.idToBlockErrorMap().put(tileId, errorList);
 		});