I have good luck with Joes juice.
However, if i am careless or in a hurry, they simply come back as has been described. It didnt work for me long term either until I figured out how it needs to be used.
I shut off all flow to the tank and slowly approach them not making them flinch........i never actually touch them, i drop the food(joes juice) from slightly above them and allow them to eat absolutely as much as they can hold which is quite a bit of the stuff. I have quite a bit of flow in my tanks so after treating i will leave the flow off for another 5 minutes. It works, they do not come back.
I would like to know what exactly Joes Juice is made from. I would bet money it IS kalk or similar, but with something else added to it that makes them want to eat it.