hmm..... i was in the exact situation as yours b4. thought my hammer were dying too. worse, the slimy body on all polyps begin to diminish and the hammers were not extending all the time.
i really cannot state what was wrong........ but during that period, i added AZNO3, a chiller, 2x 150W MH into my tank. now the hammer is back to normal.
hope this piece of info helps.