For a child to learn through Problem-Solving in Serious games, the game scaffolding mechanism has to be effective. Scaffolding is based on the Vygotzkian Zone of Proximal Development (ZPD) concept which refers to the distance between the actual development level as determined by independent problem solving and the level of potential development as determined through problem solving under adult guidance, or in collaboration with more capable peers. Scaffolds in serious games are learning stimulators. The effectiveness of these learning stimulators lies in the way they are managed or regulated. Scaffolds that are not regulated could lead to expertise-reversal effect or redundancy effect which inhibits learning. In the current classroom application of serious games, the game-based learning stimulators remain the same for everyone ("blanket scaffolding")--the learning stimulators are not managed or regulated. In order to make scaffolding in serious games more effective for classroom use, the calibration of the game's learning stimulators has to be enabled--this would help in meeting the changing needs of the learners. The concept of fading which is critical to scaffolding is introduced to serious games, to facilitate the fine-tuning of the learning stimulators to the changing needs of the learners. This paper seeks to address the issues in the design and implementation of a Fine-Tuning System for serious games based on the fading concept. Also discussed in this paper are the factors to be considered in the implementation of the Fine-Tuning System in serious games. These include fading decisions; fading and learning rates; optimal scaffolding distance; classroom culture and collaborative learning. The adverse effects of neglecting fading such as expertise-reversal effect and redundancy effect are also discussed. (Contains 1 table and 3 figures.)