diff --git a/src/app/units/Blockchain.ts b/src/app/units/Blockchain.ts
index 4a681ed..f84cf0e 100644
--- a/src/app/units/Blockchain.ts
+++ b/src/app/units/Blockchain.ts
@@ -119,9 +119,9 @@ export interface Peer {
  */
 @Singleton()
 export class Blockchain extends Unit {
-    private readonly MIN_WAIT_TIME = 30
-    private readonly MAX_WAIT_TIME = 500
-    private readonly PENALTY_INTERVAL = 100
+    private readonly MIN_WAIT_TIME = 10000
+    private readonly MAX_WAIT_TIME = 20000
+    private readonly PENALTY_INTERVAL = 1000
     private readonly MAX_PEERS_PENALTY = 10
 
     @Inject()
diff --git a/src/app/units/rtdb/Exposure.ts b/src/app/units/rtdb/Exposure.ts
index 940c086..657ff94 100644
--- a/src/app/units/rtdb/Exposure.ts
+++ b/src/app/units/rtdb/Exposure.ts
@@ -47,7 +47,7 @@ export class Exposure extends Unit {
         this.firebase.ref('exposure').on('child_added', async (snapshot) => {
             this.logging.debug('Received child_added event for exposures reference.')
             if ( !this.claim() ) return
-            await this.firebase.trylock('block', 'Exposure_child_added')
+            // await this.firebase.trylock('block', 'Exposure_child_added')
 
             const exposure: ExposureResourceItem = snapshot.val()
 
@@ -58,7 +58,7 @@ export class Exposure extends Unit {
                 await (<ExposureResource> this.make(ExposureResource)).ref().child(snapshot.key).remove()
 
             this.release()
-            await this.firebase.unlock('block')
+            // await this.firebase.unlock('block')
         })
     }
 
diff --git a/src/app/units/rtdb/Transaction.ts b/src/app/units/rtdb/Transaction.ts
index 0e9452b..47ae6d1 100644
--- a/src/app/units/rtdb/Transaction.ts
+++ b/src/app/units/rtdb/Transaction.ts
@@ -83,6 +83,7 @@ export class Transaction extends Unit {
             let groupedTransactions: [TransactionResourceItem, TransactionResourceItem][] = []
             // collection of transaction resource items
             let transactions = await TransactionResource.collect().collect()
+            await this.firebase.unlock('block')
 
             // compare each item
             await transactions.promiseMap(async transaction1 => {
@@ -111,6 +112,7 @@ export class Transaction extends Unit {
                 return false
             })
 
+            await this.firebase.trylock('block', 'Transaction_submitTransactions')
             for (const group of groupedTransactions) {
                 const block = await this.blockchain.submitTransactions(group)