Don't spray it down with nothing let the plants dry out and leave them till they wilt then re feed,But i would only add small ammounts till mould is under control.Buy a small fan and have the small fan blowing on the effected area this might help dry it out abit but mould is a hard one because once the plant get's it ,it is hard to get rid of.The only thing that i can say to help you is you must have been leaveing the plants in water or over watering.get into a habbit of watering once a week when you do water wet the plant through and re water when the top 3 ince is dry messure this by sticking your finger down the side of the pot.