Algae remover can harm or kill plants, so I would not risk it. The algae is not going to harm you plants, it just a sign the you soil is moist and get good light. You want your soil to be moist, just not wet or to dry. It's kind of hard to tell in the photo, but to me the soil in the cups looks moist at the top 1/4 to 1/3 and dry in the lower areas. You say that you are only misting them, so I'm guessing that the water is not penetrating to the lower areas of the containers were the roots are going. I would make sure you have excellent drainage in the pots and add enough water to penetrate to the bottom, then allow it to start drying out to water again.
