diff --git a/src/bench/mempool_eviction.cpp b/src/bench/mempool_eviction.cpp
index 31a392ae7..073bbde01 100644
--- a/src/bench/mempool_eviction.cpp
+++ b/src/bench/mempool_eviction.cpp
@@ -96,7 +96,7 @@ static void MempoolEviction(benchmark::State& state)
     tx7.vout[1].scriptPubKey = CScript() << OP_7 << OP_EQUAL;
     tx7.vout[1].nValue = 10 * COIN;
 
-    CTxMemPool pool(CFeeRate(1000));
+    CTxMemPool pool;
 
     while (state.KeepRunning()) {
         AddTx(tx1, 10000LL, pool);
diff --git a/src/policy/fees.cpp b/src/policy/fees.cpp
index 89220f26b..da33e4100 100644
--- a/src/policy/fees.cpp
+++ b/src/policy/fees.cpp
@@ -298,13 +298,13 @@ bool CBlockPolicyEstimator::removeTx(uint256 hash)
     }
 }
 
-CBlockPolicyEstimator::CBlockPolicyEstimator(const CFeeRate& _minRelayFee)
+CBlockPolicyEstimator::CBlockPolicyEstimator()
     : nBestSeenHeight(0), trackedTxs(0), untrackedTxs(0)
 {
-    static_assert(MIN_FEERATE > 0, "Min feerate must be nonzero");
-    minTrackedFee = _minRelayFee < CFeeRate(MIN_FEERATE) ? CFeeRate(MIN_FEERATE) : _minRelayFee;
+    static_assert(MIN_BUCKET_FEERATE > 0, "Min feerate must be nonzero");
+    minTrackedFee = CFeeRate(MIN_BUCKET_FEERATE);
     std::vector<double> vfeelist;
-    for (double bucketBoundary = minTrackedFee.GetFeePerK(); bucketBoundary <= MAX_FEERATE; bucketBoundary *= FEE_SPACING) {
+    for (double bucketBoundary = minTrackedFee.GetFeePerK(); bucketBoundary <= MAX_BUCKET_FEERATE; bucketBoundary *= FEE_SPACING) {
         vfeelist.push_back(bucketBoundary);
     }
     vfeelist.push_back(INF_FEERATE);
@@ -471,7 +471,7 @@ FeeFilterRounder::FeeFilterRounder(const CFeeRate& minIncrementalFee)
 {
     CAmount minFeeLimit = std::max(CAmount(1), minIncrementalFee.GetFeePerK() / 2);
     feeset.insert(0);
-    for (double bucketBoundary = minFeeLimit; bucketBoundary <= MAX_FEERATE; bucketBoundary *= FEE_SPACING) {
+    for (double bucketBoundary = minFeeLimit; bucketBoundary <= MAX_BUCKET_FEERATE; bucketBoundary *= FEE_SPACING) {
         feeset.insert(bucketBoundary);
     }
 }
diff --git a/src/policy/fees.h b/src/policy/fees.h
index f2f430861..dd01c90c4 100644
--- a/src/policy/fees.h
+++ b/src/policy/fees.h
@@ -179,8 +179,13 @@ static const double MIN_SUCCESS_PCT = .95;
 static const double SUFFICIENT_FEETXS = 1;
 
 // Minimum and Maximum values for tracking feerates
-static constexpr double MIN_FEERATE = 10;
-static const double MAX_FEERATE = 1e7;
+// The MIN_BUCKET_FEERATE should just be set to the lowest reasonable feerate we
+// might ever want to track.  Historically this has been 1000 since it was
+// inheriting DEFAULT_MIN_RELAY_TX_FEE and changing it is disruptive as it
+// invalidates old estimates files. So leave it at 1000 unless it becomes
+// necessary to lower it, and then lower it substantially.
+static constexpr double MIN_BUCKET_FEERATE = 1000;
+static const double MAX_BUCKET_FEERATE = 1e7;
 static const double INF_FEERATE = MAX_MONEY;
 
 // We have to lump transactions into buckets based on feerate, but we want to be able
@@ -198,7 +203,7 @@ class CBlockPolicyEstimator
 {
 public:
     /** Create new BlockPolicyEstimator and initialize stats tracking classes with default values */
-    CBlockPolicyEstimator(const CFeeRate& minRelayFee);
+    CBlockPolicyEstimator();
 
     /** Process all the transactions that have been included in a block */
     void processBlock(unsigned int nBlockHeight,
diff --git a/src/test/blockencodings_tests.cpp b/src/test/blockencodings_tests.cpp
index 311ac024f..9e4a56919 100644
--- a/src/test/blockencodings_tests.cpp
+++ b/src/test/blockencodings_tests.cpp
@@ -57,7 +57,7 @@ static CBlock BuildBlockTestCase() {
 
 BOOST_AUTO_TEST_CASE(SimpleRoundTripTest)
 {
-    CTxMemPool pool(CFeeRate(0));
+    CTxMemPool pool;
     TestMemPoolEntryHelper entry;
     CBlock block(BuildBlockTestCase());
 
@@ -156,7 +156,7 @@ public:
 
 BOOST_AUTO_TEST_CASE(NonCoinbasePreforwardRTTest)
 {
-    CTxMemPool pool(CFeeRate(0));
+    CTxMemPool pool;
     TestMemPoolEntryHelper entry;
     CBlock block(BuildBlockTestCase());
 
@@ -222,7 +222,7 @@ BOOST_AUTO_TEST_CASE(NonCoinbasePreforwardRTTest)
 
 BOOST_AUTO_TEST_CASE(SufficientPreforwardRTTest)
 {
-    CTxMemPool pool(CFeeRate(0));
+    CTxMemPool pool;
     TestMemPoolEntryHelper entry;
     CBlock block(BuildBlockTestCase());
 
@@ -272,7 +272,7 @@ BOOST_AUTO_TEST_CASE(SufficientPreforwardRTTest)
 
 BOOST_AUTO_TEST_CASE(EmptyBlockRoundTripTest)
 {
-    CTxMemPool pool(CFeeRate(0));
+    CTxMemPool pool;
     CMutableTransaction coinbase;
     coinbase.vin.resize(1);
     coinbase.vin[0].scriptSig.resize(10);
diff --git a/src/test/mempool_tests.cpp b/src/test/mempool_tests.cpp
index a3f706d9a..51b28d09f 100644
--- a/src/test/mempool_tests.cpp
+++ b/src/test/mempool_tests.cpp
@@ -54,7 +54,7 @@ BOOST_AUTO_TEST_CASE(MempoolRemoveTest)
     }
 
 
-    CTxMemPool testPool(CFeeRate(0));
+    CTxMemPool testPool;
 
     // Nothing in pool, remove should do nothing:
     unsigned int poolSize = testPool.size();
@@ -118,7 +118,7 @@ void CheckSort(CTxMemPool &pool, std::vector<std::string> &sortedOrder)
 
 BOOST_AUTO_TEST_CASE(MempoolIndexingTest)
 {
-    CTxMemPool pool(CFeeRate(0));
+    CTxMemPool pool;
     TestMemPoolEntryHelper entry;
 
     /* 3rd highest fee */
@@ -319,7 +319,7 @@ BOOST_AUTO_TEST_CASE(MempoolIndexingTest)
 
 BOOST_AUTO_TEST_CASE(MempoolAncestorIndexingTest)
 {
-    CTxMemPool pool(CFeeRate(0));
+    CTxMemPool pool;
     TestMemPoolEntryHelper entry;
 
     /* 3rd highest fee */
@@ -430,7 +430,7 @@ BOOST_AUTO_TEST_CASE(MempoolAncestorIndexingTest)
 
 BOOST_AUTO_TEST_CASE(MempoolSizeLimitTest)
 {
-    CTxMemPool pool(CFeeRate(1000));
+    CTxMemPool pool;
     TestMemPoolEntryHelper entry;
 
     CMutableTransaction tx1 = CMutableTransaction();
diff --git a/src/test/policyestimator_tests.cpp b/src/test/policyestimator_tests.cpp
index d01ef7c6e..bc2f49ef3 100644
--- a/src/test/policyestimator_tests.cpp
+++ b/src/test/policyestimator_tests.cpp
@@ -16,7 +16,7 @@ BOOST_FIXTURE_TEST_SUITE(policyestimator_tests, BasicTestingSetup)
 
 BOOST_AUTO_TEST_CASE(BlockPolicyEstimates)
 {
-    CTxMemPool mpool(CFeeRate(1000));
+    CTxMemPool mpool;
     TestMemPoolEntryHelper entry;
     CAmount basefee(2000);
     CAmount deltaFee(100);
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 79dd0fb5f..fb5820877 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -333,7 +333,7 @@ void CTxMemPoolEntry::UpdateAncestorState(int64_t modifySize, CAmount modifyFee,
     assert(int(nSigOpCostWithAncestors) >= 0);
 }
 
-CTxMemPool::CTxMemPool(const CFeeRate& _minReasonableRelayFee) :
+CTxMemPool::CTxMemPool() :
     nTransactionsUpdated(0)
 {
     _clear(); //lock free clear
@@ -343,7 +343,7 @@ CTxMemPool::CTxMemPool(const CFeeRate& _minReasonableRelayFee) :
     // of transactions in the pool
     nCheckFrequency = 0;
 
-    minerPolicyEstimator = new CBlockPolicyEstimator(_minReasonableRelayFee);
+    minerPolicyEstimator = new CBlockPolicyEstimator();
 }
 
 CTxMemPool::~CTxMemPool()
diff --git a/src/txmempool.h b/src/txmempool.h
index e919be91a..f9a9d088d 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -496,7 +496,7 @@ public:
 
     /** Create a new CTxMemPool.
      */
-    CTxMemPool(const CFeeRate& _minReasonableRelayFee);
+    CTxMemPool();
     ~CTxMemPool();
 
     /**
diff --git a/src/validation.cpp b/src/validation.cpp
index 28013306d..63918a3f3 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -81,7 +81,7 @@ uint256 hashAssumeValid;
 CFeeRate minRelayTxFee = CFeeRate(DEFAULT_MIN_RELAY_TX_FEE);
 CAmount maxTxFee = DEFAULT_TRANSACTION_MAXFEE;
 
-CTxMemPool mempool(::minRelayTxFee);
+CTxMemPool mempool;
 
 static void CheckBlockIndex(const Consensus::Params& consensusParams);