A reservoir system for use with a spray gun. The system includes a cup receptacle and a lid. The lid includes a lid body and a collar. The lid body provides a spout and a platform surrounding the spout. At least a portion of the platform forms a partial helical shape revolving about a central axis of the spout. The collar is rotatably connected to the lid body. Further, the collar includes a lid connector structure configured to connect the lid to the cup receptacle. In some embodiments, the reservoir system further includes one or more of an adaptor, a plug and a shaker core.