Apitasta can become a problem. If you have only a few less than a dozen I wouldn't worry about it but more than that and I would start to get of them.

Once they become established, they multiply rapidly. The best way to get rid of them is to use the red devil lye treatment that I recommend in the book.

It does seem drastic, but I assure you it works very well and completely safe. Use your judgment as when to take action. when you're ready Id recommend the lye treatment. If you need more info let me know

This is from pg 273 Tips & techniques

Here is what you do

• Go to a grocery store and purchase Red Devil Lye (make sure its Red Devil)(white color - not with the blue dye)
  
  
• Get your self a 3 cc syringe no needle just the plastic syringe larger than 3cc is even better if you can find a 6 or 10cc even better.
  
  
• Get these at the pharmacy or from a vet you only need one.
  
  
• Get a small container with a airtight lid a fish food container works well. Lets say you have a 2 oz dry weight fish food container rinse it out and fill with 3.4 with water. I use DI water.
  
  
• Then add 3/4 teaspoon of the red devil lye (be careful its nasty stuff!!) stir with a spoon or other utensil or put the air tight top on and shake (be careful when you shake and that the lid is on tight)
  
  
• Then simply fill the syringe with the mix and go to the Apitasta and give it a small squirt it doesn't take much < vaporized!!! next...repeat as needed. Sometimes its helpful to give then a little nudge with the syringe so they retract in the rock where the lethal dose can be more effective.
  
  
• When you do this you'll notice a whitish glob like substance, that's the lye reacting with the salt water. Simply swoosh this away with your hand and of course you do not what any of this landing on your corals. A little practice and common sense and you'll have it down in no time at all.
  
  
• Just be sure to get the plain white lye, one can will last a lifetime!

Robert