Three neglected phals, dropping leaves.

[ytriem]

I used to do fairly well with phals and could count on them to bloom in late winter and through the spring. I've been giving them a lot less attention the last couple of years, and have lost several, am down now to three, all of them slowly losing leaves and sending out aerial roots and nothing else. I've finally put pebbles under them and started watering them more attentively. I think they've lost the will to live. Any suggestions?