diff --git a/CHANGELOG.md b/CHANGELOG.md
index cf93b08b..53678ca5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
-Nothing yet.
+### Changed
+- Replaced size() in filters with DIM
 
 ## [1.1.0] - 2022-01-25
 ### Added
diff --git a/phtree/common/filter.h b/phtree/common/filter.h
index 267cba2a..46eacee3 100644
--- a/phtree/common/filter.h
+++ b/phtree/common/filter.h
@@ -134,7 +134,7 @@ class FilterAABB {
         ScalarInternal node_min_bits = MAX_MASK<ScalarInternal> << bits_to_ignore;
         ScalarInternal node_max_bits = ~node_min_bits;
 
-        for (size_t i = 0; i < prefix.size(); ++i) {
+        for (dimension_t i = 0; i < DIM; ++i) {
             if ((prefix[i] | node_max_bits) < min_internal_[i] ||
                 (prefix[i] & node_min_bits) > max_internal_[i]) {
                 return false;
@@ -154,13 +154,17 @@ class FilterAABB {
 /*
  * The sphere filter can be used to query a point tree for a sphere.
  */
-template <typename CONVERTER = ConverterIEEE<3>, typename DISTANCE = DistanceEuclidean<3>>
+template <
+    typename CONVERTER = ConverterIEEE<3>,
+    typename DISTANCE = DistanceEuclidean<CONVERTER::DimInternal>>
 class FilterSphere {
     using KeyExternal = typename CONVERTER::KeyExternal;
     using KeyInternal = typename CONVERTER::KeyInternal;
     using ScalarInternal = typename CONVERTER::ScalarInternal;
     using ScalarExternal = typename CONVERTER::ScalarExternal;
 
+    static constexpr auto DIM = CONVERTER::DimInternal;
+
   public:
     FilterSphere(
         const KeyExternal& center,
@@ -194,7 +198,7 @@ class FilterSphere {
         ScalarInternal node_max_bits = ~node_min_bits;
 
         KeyInternal closest_in_bounds;
-        for (size_t i = 0; i < prefix.size(); ++i) {
+        for (dimension_t i = 0; i < DIM; ++i) {
             // calculate lower and upper bound for dimension for given node
             ScalarInternal lo = prefix[i] & node_min_bits;
             ScalarInternal hi = prefix[i] | node_max_bits;