Backed with limelight renovating plaster why efflorescence?

[Scottishmanc52]

Hello
Can anyone explain to me why and what to do about the following issue:
The wall in my hallway (previously had damp but after it was rendered with limelight renovating plaster and then plastered with multi finish, I had a dpc. It now has efflorescence coming through the plaster and I do not know the best course of action such as painting, primer, sealant ?? etc.
Any advice suggestions will be much appreciated

 

[roy c]

Just keep brushing the salts off and when the wall dries out (totally dry) and not before, you can decorate it. If it doesn't dry out get the boys back who did it.. It will take a long time to dry out as well....(Depending on the thickness of the render /plaster). The guys should of told you that....