have you had a problem with it? worked great on mine. just like with any other thing, you have to use it as per the instructions. Just remember that you are adding a watered down Kalk Paste.
people seem to think that there is some miracle out there that will cure their tanks once and for all of aptasia. If you have them, you will always have them unless you tear down the tank and sterilize everything.
I had a rather large outbreak that I nuked with joes juice over about 2 weeks. I then bought a few peppermint shrimp to keep them in check. They don't get rid of the problem completely either. neither do copperband butterflies, lemon juice, vinegar, hydrogen peroxide, or any other thing.
It is possible to reduce the number to an almost unnoticable level using the above (and I'm sure many other) methods.