As mentioned in BeautyCare Knowledge, In order to cure breakable nails caused by genetics, mishandling of your nails like over filling and buffing, you have to take biotin tablets and apply hardener. It will make the nails stronger.
From the description of BeautyCare knowledge .In order to prevent ridges caused from picking and pushing at your nails, you have to buff the nail surface, then wipe the dust away and apply a coat of ridge filler before applying nail polish.
White marks caused by injury or pressure to the nail matrix can be covered with a dark color. The nail matrix is the area under the cuticle where the new growth happens. They cannot be hidden, as per BeautyCare knowledge.