diff --git a/conn.go b/conn.go
index 6aedf00..dc38aa5 100644
--- a/conn.go
+++ b/conn.go
@@ -11,19 +11,11 @@ type PoolConn struct {
 	hp          *heapPool
 	updatedTime time.Time
 	unusable    bool
-	closed      bool
 }
 
 // Close put the connection back to pool if possible.
 // Executed by multi times is ok.
 func (pc *PoolConn) Close() error {
-	if pc.closed {
-		return nil
-	}
-	defer func() {
-		pc.closed = true
-	}()
-
 	if pc.unusable {
 		return pc.close()
 	}
diff --git a/heap.go b/heap.go
index 5ffc87f..0b4f28c 100644
--- a/heap.go
+++ b/heap.go
@@ -41,7 +41,7 @@ type heapPool struct {
 	initialCap  int
 	maxCap      int
 	maxIdle     int
-	idletime    time.Duration
+	idleTime    time.Duration
 	maxLifetime time.Duration
 	cleanerCh   chan struct{}
 
@@ -65,9 +65,9 @@ func NewHeapPool(config *PoolConfig) (Pool, error) {
 	if config.MaxIdle > 0 {
 		maxIdle = config.MaxIdle
 	}
-	idletime := 2 * time.Minute
+	idleTime := 2 * time.Minute
 	if config.Idletime > 0 {
-		idletime = config.Idletime
+		idleTime = config.Idletime
 	}
 	maxLifetime := 15 * time.Minute
 	if config.MaxLifetime > 0 {
@@ -78,7 +78,7 @@ func NewHeapPool(config *PoolConfig) (Pool, error) {
 		initialCap:  initialCap,
 		maxCap:      maxCap,
 		maxIdle:     maxIdle,
-		idletime:    idletime,
+		idleTime:    idleTime,
 		maxLifetime: maxLifetime,
 		cleanerCh:   make(chan struct{}),
 		factory:     config.Factory,
@@ -126,6 +126,7 @@ func (hp *heapPool) Get() (net.Conn, error) {
 			hp.mu.Unlock()
 			return pc, nil
 		}
+		go pc.close()
 	}
 	hp.mu.Unlock()
 
@@ -178,7 +179,7 @@ func (hp *heapPool) Len() int {
 }
 
 func (hp *heapPool) cleaner() {
-	ticker := time.NewTicker(hp.idletime / 2)
+	ticker := time.NewTicker(hp.idleTime / 2)
 	defer ticker.Stop()
 	for {
 		select {
@@ -189,11 +190,13 @@ func (hp *heapPool) cleaner() {
 				pc := (*hp.freeConn)[0]
 				interval := time.Now().Sub(pc.updatedTime)
 				if interval >= hp.maxLifetime {
-					heap.Pop(hp.freeConn).(*PoolConn).close()
+					_p := heap.Pop(hp.freeConn).(*PoolConn)
+					go _p.close()
 					continue
 				}
-				if interval >= hp.idletime && hp.freeConn.Len() > hp.maxIdle {
-					heap.Pop(hp.freeConn).(*PoolConn).close()
+				if interval >= hp.idleTime && hp.freeConn.Len() > hp.maxIdle {
+					_p := heap.Pop(hp.freeConn).(*PoolConn)
+					go _p.close()
 					continue
 				}
 				break
diff --git a/heap_test.go b/heap_test.go
index 781fabc..0d02dfe 100644
--- a/heap_test.go
+++ b/heap_test.go
@@ -31,11 +31,17 @@ func TestNew(t *testing.T) {
 
 func TestPool(t *testing.T) {
 	p, _ := newHeapPool()
+	if p.Len() != InitialCap {
+		t.Errorf("pool len is invalid, excepted: %v, bug get: %v", InitialCap, p.Len())
+	}
 
 	conn, err := p.Get()
 	if err != nil {
 		t.Errorf("Get error: %s", err)
 	}
+	if p.Len() != InitialCap-1 {
+		t.Errorf("pool len is invalid, excepted: %v, bug get: %v", InitialCap-1, p.Len())
+	}
 
 	_, ok := conn.(*PoolConn)
 	if !ok {
@@ -45,7 +51,6 @@ func TestPool(t *testing.T) {
 	if err := conn.Close(); err != nil {
 		t.Errorf("Pool Conn close error:%v", err)
 	}
-
 	if p.Len() != InitialCap {
 		t.Errorf("Pool size is invalid, size:%v", p.Len())
 	}
@@ -58,6 +63,30 @@ func TestPool(t *testing.T) {
 	}
 }
 
+func TestHeapPool_Len(t *testing.T) {
+	p, _ := newHeapPool()
+	defer p.Close()
+
+	for i := 1; i <= 50; i++ {
+		if p.Len() != InitialCap {
+			t.Errorf("pool len is invalid, excepted: %v, bug get: %v, i: %v", InitialCap, p.Len(), i)
+		}
+
+		conn, err := p.Get()
+		if err != nil {
+			t.Errorf("Get error: %s", err)
+		}
+		if p.Len() != InitialCap-1 {
+			t.Errorf("pool len is invalid, excepted: %v, bug get: %v, i: %v", InitialCap-1, p.Len(), i)
+		}
+
+		conn.Close()
+		if p.Len() != InitialCap {
+			t.Errorf("pool len is invalid, excepted: %v, bug get: %v, i: %v", InitialCap, p.Len(), i)
+		}
+	}
+}
+
 func TestPriorityQueue(t *testing.T) {
 	p, _ := newHeapPool()
 	conn1, err := p.Get()