diff --git a/testnet/README.md b/testnet/README.md
index 3f7ea9f6..42e153d8 100644
--- a/testnet/README.md
+++ b/testnet/README.md
@@ -26,6 +26,7 @@
 - Make sure to reference testnet blockchain config file: `"blockchainConfig": "testchain.json",`
 - It is a good idea to use a separate database: `"repositoryPath": "db-testnet",`
 - You might also need to add `"bitcoinNet": "TEST3",` and `"litecoinNet": "TEST3",`
+- Also make sure to use a custom `listenPort` (not 62391 or 12391) to ensure that transactions remain isolated to your testnet.
 
 ## Other nodes
 
@@ -59,7 +60,7 @@ Just add this setting:
 "singleNodeTestnet": true
 ```
 This will automatically allow multiple consecutive blocks to be minted, as well as setting minBlockchainPeers to 0.
-Remember to put these values back after introducing other nodes
+Remember to put these values back after introducing other nodes.
 
 ## Fixed network
 
@@ -119,11 +120,12 @@ Your options are:
 ## Quick start
 Here are some steps to quickly get a single node testnet up and running with a generic minting account:
 1. Start with template `settings-test.json`, and `testchain.json` which can be found in this folder. Copy/move them to the same directory as the jar.
-2. Make sure feature triggers and other timestamp/height activations are correctly set. Generally these would be `0` so that they are enabled from the start.
-3. Set a recent genesis `timestamp` in testchain.json, and add this reward share entry:
+2. Set a custom `listenPort` in settings-test.json (not 62391 or 12391) to ensure that transactions remain isolated to your testnet.
+3. Make sure feature triggers and other timestamp/height activations are correctly set. Generally these would be `0` so that they are enabled from the start.
+4. Set a recent genesis `timestamp` in testchain.json, and add this reward share entry:
 `{ "type": "REWARD_SHARE", "minterPublicKey": "DwcUnhxjamqppgfXCLgbYRx8H9XFPUc2qYRy3CEvQWEw", "recipient": "QbTDMss7NtRxxQaSqBZtSLSNdSYgvGaqFf", "rewardSharePublicKey": "CRvQXxFfUMfr4q3o1PcUZPA4aPCiubBsXkk47GzRo754", "sharePercent": 0 },`
-4. Start the node, passing in settings-test.json, e.g: `java -jar qortal.jar settings-test.json`
-5. Once started, add the corresponding minting key to the node:
+5. Start the node, passing in settings-test.json, e.g: `java -jar qortal.jar settings-test.json`
+6. Once started, add the corresponding minting key to the node:
 `curl -X POST "http://localhost:62391/admin/mintingaccounts" -d "F48mYJycFgRdqtc58kiovwbcJgVukjzRE4qRRtRsK9ix"`
-6. Alternatively you can use your own minting account instead of the generic one above.
-7. After a short while, blocks should be minted from the genesis timestamp until the current time.
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+7. Alternatively you can use your own minting account instead of the generic one above.
+8. After a short while, blocks should be minted from the genesis timestamp until the current time.
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