I have a wallet with 0.1XMR in it. I did a test transaction of 0.00001XMR, which I sent to another address owned by an exchange.
After sending this tiny transaction, my unlocked balance went from 0.1 to 0.
I need to be able to transfer many small amounts of XMR, as I am running a faucet service. Why is my total balance now locked, and how do I prevent this in the future?