If you are not adding an ammonia source, you are not cycling. You are just building up nitrates from the old substrate. If you have no other source, you can feed the tank as if there were fish in it and that will give you some ammonia from the food breaking down.
You may have picked up some of the right bacteria from that old substrate if it has stayed wet since you last had some fish in it but they will not be reproducing without "food". If you are still looking for endlers, I have some but don't know how to ship properly. You can see in my profile where I am so will know if I am close enough to help.
You may have picked up some of the right bacteria from that old substrate if it has stayed wet since you last had some fish in it but they will not be reproducing without "food". If you are still looking for endlers, I have some but don't know how to ship properly. You can see in my profile where I am so will know if I am close enough to help.