Green torch sweeper tentacles

I have a Red Sea Reefer 28 gallon with a green torch coral who has constantly shown long sweeper tentacles throughout the day and I've had to move it because of this. The sweepers are close to 6 inches long and have already stung my Acan and monti. Is there something that I can do to stop the tentacles form being so long? What causes them to have such long sweepers?